It is of vital importance to improve the long-term and photostability of organic photovoltaics,including organic solar cells(OSCs)and organic photodetectors(OPDs),for their ultimate industrialization.Herein,two series...It is of vital importance to improve the long-term and photostability of organic photovoltaics,including organic solar cells(OSCs)and organic photodetectors(OPDs),for their ultimate industrialization.Herein,two series of terpolymers featuring with an antioxidant butylated hydroxytoluene(BHT)-terminated side chain,PTzBI-EHp-BTBHTx and N2200-BTBHTx(x=0.05,0.1,0.2),are designed and synthesized.It was found that incorporating appropriate ratio of benzothiadiazole(BT)with BHT side chains on the conjugated backbone would induce negligible effect on the molecular weight,absorption spectra and energy levels of polymers,however,which would obviously enhance the photostability of these polymers.Consequently,all-polymer solar cells(all-PSCs)and photodetectors were fabricated,and the all-PSC based on PTzBI-EHp-BTBHT0.05:N2200 realized an optimal power conversion efficiency(PCE)approaching~10%,outperforming the device based on pristine PTzBI-EHp:N2200.Impressively,the all-PSCs based on BHT-featuring terpolymers displayed alleviated PCEs degradation under continuous irradiation for 300 h due to the improved morphological and photostability of active layers.The OPDs based on BHT-featuring terpolymers achieved a lower dark current at−0.1 bias,which could be stabilized even after irradiation over 400 h.This study provides a feasible approach to develop terpolymers with antioxidant efficacy for improving the lifetime of OSCs and OPDs.展开更多
Due to the complicated film formation kinetics, morphology control remains a major challenge for the development of efficient and stable all-polymer solar cells(all-PSCs). To overcome this obstacle, the sequential dep...Due to the complicated film formation kinetics, morphology control remains a major challenge for the development of efficient and stable all-polymer solar cells(all-PSCs). To overcome this obstacle, the sequential deposition method is used to fabricate the photoactive layers of all-PSCs comprising a polymer donor PTzBI-oF and a polymer acceptor PS1. The film morphology can be manipulated by incorporating amounts of a dibenzyl ether additive into the PS1 layer. Detailed morphology investigations by grazing incidence wide-angle X-ray scattering and a transmission electron microscope reveal that the combination merits of sequential deposition and DBE additive can render favorable crystalline properties as well as phase separation for PTzBI-oF:PS1 blends. Consequently, the optimized all-PSCs delivered an enhanced power conversion efficiency(PCE) of 15.21%along with improved carrier extraction and suppressed charge recombination. More importantly, the optimized all-PSCs remain over 90% of their initial PCEs under continuous thermal stress at 65 °C for over 500 h. This work validates that control over microstructure morphology via a sequential deposition process is a promising strategy for fabricating highly efficient and stable all-PSCs.展开更多
Polymer acceptors based on extended fused ring p skeleton has been proven to be promising candidates for all-polymer solar cells(all-PSCs), due to their remarkable improved light absorption than the traditional imide-...Polymer acceptors based on extended fused ring p skeleton has been proven to be promising candidates for all-polymer solar cells(all-PSCs), due to their remarkable improved light absorption than the traditional imide-based polymer acceptors. To expand structural diversity of the polymer acceptors, herein,two polymer acceptors PSF-IDIC and PSi-IDIC with extended fused ring p skeleton are developed by copolymerization of 2,20-((2 Z,20 Z)-((4,4,9,9-tetrahexadecyl-4,9-dihydro-s-indaceno [1,2-b:5,6-b']dithio phene-2,7-diyl)bis(methanylylidene))bis(3-oxo-2,3-dihydro-1 H-indene-2,1-diylidene))dimalononitrile(IDIC-C16) block with sulfur(S) and fluorine(F) functionalized benzodithiophene(BDT) unit and silicon(Si) atom functionalized BDT unit, respectively. Both polymer acceptors exhibit strong light absorption.The PSF-IDIC exhibits similar energy levels and slightly higher absorption coefficient relative to the PSi-IDIC. After blended with the donor polymer PM6, the functional atoms on the polymer acceptors show quite different effect on the device performance. Both of the acceptors deliver a notably high open circuit voltage(V_(OC)) of the devices, but PSi-IDIC achieves higher V OCthan PSF-IDIC. All-PSC based on PM6:PSi-IDIC attains a power conversion efficiency(PCE) of 8.29%, while PM6:PSF-IDIC-based device achieves a much higher PCE of 10.18%, which is one of the highest values for the all-PSCs reported so far. The superior device performance of PM6:PSF-IDIC is attributed to its higher exciton dissociation and charge transport, decreased charge recombination, and optimized morphology than PM6:PSi-IDIC counterpart. These results suggest that optimizing the functional atoms of the side chain provide an effective strategy to develop high performance polymer acceptors for all-PSCs.展开更多
All-polymer solar cells(all-PSCs)possess attractive merits including superior thermal stability and mechanical flexibility for large-area roll-to-roll processing.Introducing flexible conjugation-break spacers(FCBSs)in...All-polymer solar cells(all-PSCs)possess attractive merits including superior thermal stability and mechanical flexibility for large-area roll-to-roll processing.Introducing flexible conjugation-break spacers(FCBSs)into backbones of polymer donor(P_(D))or polymer acceptor(P_(A))has been demonstrated as an efficient approach to enhance both the photovoltaic(PV)and mechanical properties of the all-PSCs.However,length dependency of FCBS on certain all-PSC related properties has not been systematically explored.In this regard,we report a series of new non-conjugated P_(A)s by incorporating FCBS with various lengths(2,4,and 8 carbon atoms in thioalkyl segments).Unlike com-mon studies on so-called side-chain engineering,where longer side chains would lead to better solubility of those resulting polymers,in this work,we observe that the solubilities and the resulting photovoltaic/mechanical properties are optimized by a proper FCBS length(i.e.,C2)in P_(A) named PYTS-C2.Its all-PSC achieves a high efficiency of 11.37%,and excellent mechanical robustness with a crack onset strain of 12.39%,significantly superior to those of the other P_(A)s.These results firstly demonstrate the effects of FCBS lengths on the PV performance and mechanical properties of the all-PSCs,providing an effective strategy to fine-tune the structures of P_(A)s for highly efficient and mechanically robust PSCs.展开更多
In recent years, a large library of n-type polymers have been developed and widely used as acceptor materials to replace fullerene derivatives in polymer solar cells(PSCs), stimulating the rapid expansion of research ...In recent years, a large library of n-type polymers have been developed and widely used as acceptor materials to replace fullerene derivatives in polymer solar cells(PSCs), stimulating the rapid expansion of research on so-called all-polymer solar cells(a PSCs). In particular, rylene diimide-based n-type polymer acceptors have attracted broad research interest due to their high electron mobility, suitable energy levels, and strong light-harvesting ability in the visible region. Among various polymer acceptors, rylene diimide-based polymers presented best performances when served as the acceptor materials in a PSCs. Typically, a record power conversion efficiency(PCE) of 7.7% was very recently achieved from an a PSC with a rylene diimide polymer derivative as the acceptor component. In this review, we highlight recent progress of n-type polymers originated from two significant classes of rylene diimide units, namely naphthalene diimide(NDI) and perylene diimide(PDI), as well as their derivatives for a PSC applications.展开更多
A-DA'D-A type polymerized small-molecule acceptors(PSMAs) have very recently received wide attention because they possess advantages such as synthetic flexibility, narrowed bandgap, low energy loss, and impressive...A-DA'D-A type polymerized small-molecule acceptors(PSMAs) have very recently received wide attention because they possess advantages such as synthetic flexibility, narrowed bandgap, low energy loss, and impressive mechanical properties. With efforts on design and synthesis of PSMAs and polymer donors, significant progress has been made on all polymer solar cells(allPSCs) with power conversion efficiencies exceeding 18%. In this review, we focus on structure-property-performance relationships of the A-DA'D-A type PSMAs. First, we in-depth review the regio-random, regio-regular, and random ternary series by focusing on their structural modification such as from aspects of side-chains, halogenation, selenophene-containing and linkers, respectively. Second, we review the mechanically flexible and stretchable properties, which helps to find structural gene that correlates the mechanical properties. Third, we review the impressive small energy loss. In all, this review provides structural and material's clues, helpfully for designing high-performance all-PSCs.展开更多
Comprehensive Summary The regioregularity induced by the isomers of the end-groups has been widely recognized as a key factor that determines the photovoltaic properties of polymerized small molecular acceptors(PSMAs)...Comprehensive Summary The regioregularity induced by the isomers of the end-groups has been widely recognized as a key factor that determines the photovoltaic properties of polymerized small molecular acceptors(PSMAs)in all-polymer solar cells(all-PSCs).However,the influence of regioregularity on the photovoltaic properties of non-fused PSMAs has not been explored yet.In this contribution,two regioregular non-fused PSMAs,PFBTz-T-γand PFBTz-T-δ,were synthesized for the first time by using the monomers with isomeric pure end-groups.Compared with PFBTz-T-δ,PFBTz-T-γhas more compact and more ordered packing in solid state,which results in a more red-shifted optical absorption and a higher electron mobility.More remarkably,PFBTz-T-γand PFBTz-T-δexhibited huge difference in photovoltaic performance in all-PSCs,which offered the power conversion efficiencies(PCEs)of 9.72%and 0.52%,respectively.Further studies have unveiled that the higher PCE of PFBTz-T-γis due to more efficient exciton dissociation,higher and more balanced electron/hole mobility,and less charge recombination as a result of favorable morphology of the blend film.This work demonstrates that the development of regioregular non-fused PSMAs by tuning the polymerization sites is an effective strategy for obtaining high-efficiency all-PSCs.展开更多
P3HT stands out from numerous polymer donors owing to the merits of low cost and high scalability of synthesis.However,the photovoltaic performance of P3HT-based blends lags significantly behind the state-of-the-art s...P3HT stands out from numerous polymer donors owing to the merits of low cost and high scalability of synthesis.However,the photovoltaic performance of P3HT-based blends lags significantly behind the state-of-the-art systems,especially for all-polymer solar cells(APSCs) that generally show efficiency of around 3%–4% due to the lack of matched polymer acceptors.Herein,a polymer acceptor,named IDTBTC8-CN,was designed and synthesized with indacenodithiophene(IDT) and mono-cyano(CN)-substituted benzothiadiazole(BT-CN) as building blocks.Introducing a CN group endowed the polymer with decreased bandgap,and apparent n-type charge transport character despite the relatively high energy levels.Additionally,IDTBTC8-CN showed largely improved miscibility with P3HT,compared with that of BT-based control polymer IDTBTC8.The high miscibility between P3HT and IDTBTC8-CN as well as the amorphous aggregation behavior of IDTBTC8-CN enabled a broad manipulation room for the blend film to acquire favorable morphology.Eventually,a champion efficiency of 8.30% was achieved,in sharp contrast to that of the IDTBTC8-based system(1.21%).Such efficiency is a new record for P3HT-based APSCs reported so far.Moreover,P3HT:IDTBTC8-CN blend film also exhibited excellent mechanical robustness.This study implies the guidance of molecular design of the polymer acceptors and morphology control for P3HT-based APSCs.展开更多
Narrow-bandgap n-type polymers are essential for advancing the development of all-polymer solar cells(all-PSCs).Herein,we developed a novel polymer acceptor PNT withπ-extended 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]nap...Narrow-bandgap n-type polymers are essential for advancing the development of all-polymer solar cells(all-PSCs).Herein,we developed a novel polymer acceptor PNT withπ-extended 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile(CPNM)end groups.Compared to commonly used 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1ylidene)malononitrile(IC)units,CPNM units have a further extended fused ring,providing the PNT polymer with extended absorption into the near-IR region(903 nm)and exhibiting a narrow optical bandgap(1.37 eV).Furthermore,PNT exhibits a high electron mobility(6.79×10^(−4) cm^(2)·V^(−1)·S^(−1))and a relatively high-lying lowest unoccupied molecular orbital(LUMO)energy level of−3.80 eV.When blended with PBDB-T,all-PSC achieves a power conversion efficiency(PCE)of 13.7%and a high short-circuit current density(JSC)of 24.4 mA·cm^(−2),mainly attributed to broad absorption(600—900 nm)and efficient charge separation and collection.Our study provides a promising polymer acceptor for all-PSCs and demonstrates thatπ-extended CPNM units are important to achieve high-performance for all-PSCs.展开更多
The development of polymerized fused-ring small molecule acceptors(FRA-PAs) has boosted the performance of all-polymer solar cells(all-PSCs).However,these FRA-PAs suffer from lengthy synthesis steps and high productio...The development of polymerized fused-ring small molecule acceptors(FRA-PAs) has boosted the performance of all-polymer solar cells(all-PSCs).However,these FRA-PAs suffer from lengthy synthesis steps and high production costs due to the high degree of synthetic complexity for fused-ring small molecule acceptors(FRAs).Furthermore,most FRA-PAs exhibit strong batch-to-batch variation,limiting further industrial applications.Herein,we designed and synthesized asymmetric non-fused electron-deficient building block TIC-Br with a simple structure(only three synthetic steps),showing a planar configuration,excellent electron affinity,and large dipole moment.A simple polymer acceptor PTIB was further developed by polymerization of TIC-Br and sensitized fluorinated-thienyl benzodithiophene(BDT-TF-Sn).PTIB exhibits a broad absorption from 300 to 800 nm,a suitable lowest unoccupied molecular orbital(LUMO) energy level of-3.86 e V,and moderate electron mobility(1.02×10^(-4)cm^(2)V^(-1)s^(-1)).When matched with PM6,the device achieved the best PCE of 10.11%with a high V_(OC) of 0.97 V,which is one of the highest among those reported all-PSCs.More importantly,PTIB exhibits a lower synthetic complexity index(SC=35.0%)and higher figure-of-merit values(FOM=29.0%) than all the reported high-performance PAs.The polymer also exhibits excellent batch-to-batch reproducibility and great potential for scale-up fabrication.This study indicates that TIC-Br is a promising building block for constructing low-cost polymer acceptors for large-scale applications in all-PSCs.展开更多
One important subject in the field of all-polymer solar cells (all-PSCs) is the exploration of electron-deficient building blocks with optimized physicochemical properties to promote the performance of polymer accepto...One important subject in the field of all-polymer solar cells (all-PSCs) is the exploration of electron-deficient building blocks with optimized physicochemical properties to promote the performance of polymer acceptors. Here, two ladder-type heteroheptacene-containing small-molecule acceptors with branched 2-octyldodecyl or 2-hexyldecyl side-chains are synthesized and polymerized with the thiophene co-monomer to afford polymer acceptors (PW-OD and PW-HD) with strong near-infrared absorption. Experimental results reveal that the alkyl chain length has a large impact on the molecular packing behavior of the resulting polymers, which in turn affects their light-absorbing and charge transport properties, and thus the photovoltaic performance of the final devices. When blended with the polymer donor PM6, PW-HD-based all-PSCs deliver a higher power conversion efficiency (PCE) of 9.12% compared to the PCE of 6.47% for the PW-OD-based all-PSCs, mainly due to its more ordered inter-chain packing and more favorable blend morphology. This work provides a promising building block for the development of high-performance narrow-bandgap polymer acceptors and highlights the importance of side-chain substitution in optimizing the photovoltaic performance of polymer acceptors.展开更多
The active layer of all polymer solar cells(all-PSCs)is composed of a blend of a p-type conjugated polymer(p-CP)as donor and an n-type conjugated polymer(n-CP)as acceptor.All-PSCs possess the advantages of light weigh...The active layer of all polymer solar cells(all-PSCs)is composed of a blend of a p-type conjugated polymer(p-CP)as donor and an n-type conjugated polymer(n-CP)as acceptor.All-PSCs possess the advantages of light weight,thin active layer,mechanical flexibility,low cost solution processing and high stability,but the power conversion efficiency(PCE)of the all-PSCs was limited by the poor photovoltaic performance of the n-CP acceptors before 2016.Since the report of the strategy of polymerized small molecule acceptors(PSMAs)in 2017,the photovoltaic performance of the PSMA-based n-CPs improved rapidly,benefitted from the development of the A-DA’D-A type small molecule acceptors(SMAs).PCE of the all-PSCs based on the PSMA acceptors reached 17%-18%recently.In this review article,we will introduce the development history of the n-CPs,especially the recent research progress of the PSMAs.Particularly,the structure-property relationship of the PSMAs is introduced and discussed.Finally,current challenges and prospects of the n-CP acceptors are analyzed and discussed.展开更多
The stability issue is one of the key factors hindering the commercial application of organic solar cells.All-polymer organic solar cell is one of the effective ways to solve the stability problem.In this work,we desi...The stability issue is one of the key factors hindering the commercial application of organic solar cells.All-polymer organic solar cell is one of the effective ways to solve the stability problem.In this work,we designed and synthesized two polymer donor materials PBDT and PDTBDT with different conjugation ranges,and demonstrated for the first time that extending the conjugation range of donor materials in all polymer solar cells can significantly improve device efficiency and stability.The experimental results of materials and devices show that PDTBDT with a larger conjugation range has stronger crystallinity and a more planar structure,which endows the active layer in its corresponding device with higher exciton dissociation probability,lower carrier recombination probability,more balanced charge transport properties and more favorable film morphology.As a result,the PDTBDT:PYF-T-o devices display an outstanding PCE of 13.38%,which is much higher than PBDT with smaller conjugation range based devices.Moreover,the PDTBDT:PYF-T-o device retains 0.86 of the initial PCE after over 500 h in the air atmosphere,exhibiting significantly improved stability.The improved stability is attributed to the enhanced moisture and air tolerance of active layer film thanks to the strong crystallinity of the donor material.These results demonstrate that the conjugation expansion strategy is one of the effective ways to obtain efficient and stable all-polymer organic solar cells.展开更多
The slot-die coating is recognized as the most compatible method for the roll-to-roll(R2R)processing of large-area flexible organic solar cells(OSCs).However,the photovoltaic performance of the large-area flexible all...The slot-die coating is recognized as the most compatible method for the roll-to-roll(R2R)processing of large-area flexible organic solar cells(OSCs).However,the photovoltaic performance of the large-area flexible all-polymer solar cells was significantly lagging behind that of polymer donors with small molecule non-fullerene acceptors devices.In this work,the 1 cm^(2) flexible device of an all-polymer system,PTQ10:PYF-T-o,fabricated by slot-die coating,achieves an excellent efficiency of 11.24%via controlling the coating temperatures.It is found that,compared with the donor,the crystallinity of PYF-T-o plays a crucial role in device performance.The all-polymer flexible devices show superior mechanical bending stability,maintaining an efficiency of over 95%of the initial value during a 1000-cycle bending test.展开更多
Adva nces in orga nic photovoltaic tech no logies have been geared toward industrial high-throughput printing manufacturing,which requires in sensitivity of photovoltaic performance reg a rd i ng to the light-harvesti...Adva nces in orga nic photovoltaic tech no logies have been geared toward industrial high-throughput printing manufacturing,which requires in sensitivity of photovoltaic performance reg a rd i ng to the light-harvesting layer thickness.However,the thickness of light-harvesti ng layer for all polymer solar cells(all-PSCs)is often limited to about 100 nm due to the dramatically decreased fill factor upon increasing film thickness,which hampers the light harvesting capability to in crease the power con versio n efficie ncy,and is un favorable for fabricating large-area devices.Here we dem on strate that by tuning the bulk heterojuncti on morphology using a non-halogenated solvent,cyclopentyl methyl ether,in the presence of a gree n solve nt additive of dibenzyl ether,the power con versio n efficie ncy of all-PSCs with photoactive layer thick nesses of over 500 nm reached an impressively high value of 9%.The gen eric applicability of this gree n solvent additive to boost the power conversion efficiency of thick-film devices is also validated in various bulk heterojunction active layer systems,thus representing a promising approach for the fabrication of all-PSCs toward industrial production,as well as further commercialization.展开更多
The non-fully conjugated polymer as a new class of acceptor materials has shown some advantages over its small molecular counterpart when used in photoactive layers for all-polymer solar cells(all-PSCs),despite a low ...The non-fully conjugated polymer as a new class of acceptor materials has shown some advantages over its small molecular counterpart when used in photoactive layers for all-polymer solar cells(all-PSCs),despite a low power conversion efficiency(PCE)caused by its narrow absorption spectra.Herein,a novel non-fully conjugated polymer acceptor PFY-2TS with a low bandgap of~1.40 eV was developed,via polymerizing a largeπ-fused small molecule acceptor(SMA)building block(namely YBO)with a non-conjugated thioalkyl linkage.Compared with its precursor YBO,PFY-2TS retains a similar low bandgap but a higher LUMO level.Moreover,compared with the structural analog of YBO-based fully conjugated polymer acceptor PFY-DTC,PFY-2TS shows a similar absorption spectrum and electron mobility,but significantly different molecular crystallinity and aggregation properties,which results in optimal blend morphology with a polymer donor PBDB-T and physical processes of the device in all-PSCs.As a result,PFY-2TS-based all-PSCs achieved a PCE of 12.31%with a small energy loss of 0.56 eV enabled by the reduced non-radiative energy loss(0.24 eV),which is better than that of 11.08%for the PFY-DTC-based ones.Our work clearly demonstrated that non-fully conjugated polymers as a new class of acceptor materials are very promising for the development of high-performance all-PSCs.展开更多
We report all-polymer solar cells(All-PSCs) with record-high power conversion efficiency(PCE) through tuning the molecular weights of the polymer donor(PBDB-T) to form optimal active layer morphology. By combining the...We report all-polymer solar cells(All-PSCs) with record-high power conversion efficiency(PCE) through tuning the molecular weights of the polymer donor(PBDB-T) to form optimal active layer morphology. By combining the polymer donors with a newly reported polymer acceptor(PJ1), an unprecedented high PCE of 15.4% and fill factor over 75% were achieved for the AllPSCs with the medium molecular weight polymer donor(PBDB-TMW), which is the highest value for All-PSCs reported so far.Detailed morphology investigation revealed that the proper phase separation in the PBDB-TMW:PJ1 blend should account for the superior device performance as PBDB-TMW exhibits appropriate miscibility with the polymer acceptor PJ1. These results demonstrated that the device performance of All-PSCs could be fully comparable to that of small molecular acceptor-based PSCs. The formation of optimized morphology via precise control of molecular weights of polymer donors and acceptors is crucial to achieve this goal.展开更多
Bulk-heterojunction polymer solar cells(PSCs)have attracted considerable attention owning to their potential for fabricating flexible,light-weight and large area solar cell panels via high-throughput roll-to-roll tech...Bulk-heterojunction polymer solar cells(PSCs)have attracted considerable attention owning to their potential for fabricating flexible,light-weight and large area solar cell panels via high-throughput roll-to-roll technologies.Compared with conventional PSCs comprising small molecule acceptors,such as fullerenes,all-polymer solar cells(all-PSCs)containing blends of p-type/n-type polymers in the photoactive layer provide advantages including展开更多
Despite the significant progress made recently in all-polymer solar cells(all-PSCs),it is still quite challenging to achieve high open-circuit voltage(V_(oc))and short-circuit current density(J_(sc))simultaneously in ...Despite the significant progress made recently in all-polymer solar cells(all-PSCs),it is still quite challenging to achieve high open-circuit voltage(V_(oc))and short-circuit current density(J_(sc))simultaneously in order to further improve their performance.The recent strategy of using selenophene to replace thiophene on the Y6 based polymer acceptors has resulted in significantly improved J_(sc)s of the resulting all-PSCs.However,such modifications have also depressed V_(oc),which compromises the overall performance of the devices.Herein,we present the design and synthesis of a novel polymer acceptor,PYT-1S1Se,created by inserting an asymmetrical selenophene-fused framework to precisely manipulate optical absorption and electronic properties.Compared with the selenium-free analog,PYT-2S,and symmetrical selenium-fused analog,PYT-2Se,the PYT-1S1Se derived all-PSCs not only deliver optimized J_(sc)(24.1 mA cm^(−2))and V_(oc)(0.926 V)metrics,but also exhibit a relatively low energy loss of 0.502 eV.Consequently,these devices obtain a record-high power conversion efficiency(PCE)of 16.3%in binary all-PSCs.This work demonstrates an effective molecular design strategy for balancing the trade-off between V_(oc) and J_(sc) to achieve highefficiency all-PSCs.展开更多
The open-circuit voltage(Voc) of all-polymer solar cells(all-PSCs) is typically lower than 0.9 V even for the most efficient ones.Large energy loss is the main reason for limiting Voc and efficiency of all-PSCs. Herei...The open-circuit voltage(Voc) of all-polymer solar cells(all-PSCs) is typically lower than 0.9 V even for the most efficient ones.Large energy loss is the main reason for limiting Voc and efficiency of all-PSCs. Herein, through materials design using electron deficient building blocks based on bithiophene imides, the lowest unoccupied molecular orbital(LUMO) energy levels of polymer acceptors can be effectively tuned, which resulted in a reduced energy loss induced by charge generation and recombination loss due to the suppressed charge-transfer(CT) state absorption. Despite a negligible driving force, all-PSC based on the polymer donor and acceptor combination with well-aligned energy levels exhibited efficient charge transfer and achieved an external quantum efficiency over 70% while maintaining a large Voc of 1.02 V, leading to a 9.21% efficiency. Through various spectroscopy approaches, this work sheds light on the mechanism of energy loss in all-PSCs, which paves an avenue to achieving efficient all-PSCs with large Voc and drives the further development of all-PSCs.展开更多
基金The work was financially supported by National Key Research and Development Program of China(2019YFA0705900,2022YFB4200400)funded by MOSTthe Basic and Applied Basic Research Major Program of Guangdong Province(No.2019B030302007)+2 种基金the National Natural Science Foundation of China(No.U21A6002)Guangdong-Hong Kong-Macao joint laboratory of optoelectronic and magnetic functional materials(No.2019B121205002)C.Z.acknowledges the financial support by Basic and Applied Basic Research Major Program of Guangdong Province(No.202201010270).
文摘It is of vital importance to improve the long-term and photostability of organic photovoltaics,including organic solar cells(OSCs)and organic photodetectors(OPDs),for their ultimate industrialization.Herein,two series of terpolymers featuring with an antioxidant butylated hydroxytoluene(BHT)-terminated side chain,PTzBI-EHp-BTBHTx and N2200-BTBHTx(x=0.05,0.1,0.2),are designed and synthesized.It was found that incorporating appropriate ratio of benzothiadiazole(BT)with BHT side chains on the conjugated backbone would induce negligible effect on the molecular weight,absorption spectra and energy levels of polymers,however,which would obviously enhance the photostability of these polymers.Consequently,all-polymer solar cells(all-PSCs)and photodetectors were fabricated,and the all-PSC based on PTzBI-EHp-BTBHT0.05:N2200 realized an optimal power conversion efficiency(PCE)approaching~10%,outperforming the device based on pristine PTzBI-EHp:N2200.Impressively,the all-PSCs based on BHT-featuring terpolymers displayed alleviated PCEs degradation under continuous irradiation for 300 h due to the improved morphological and photostability of active layers.The OPDs based on BHT-featuring terpolymers achieved a lower dark current at−0.1 bias,which could be stabilized even after irradiation over 400 h.This study provides a feasible approach to develop terpolymers with antioxidant efficacy for improving the lifetime of OSCs and OPDs.
基金financially supported by Guangdong Major Project of Basic and Applied Basic Research (No.2019B030302007)National Key Research and Development Program of China (No. 2019YFA0705900) funded by MOSTthe financial support by State Key Lab of Luminescent Materials and Devices,South China University of Technology (Skllmd-2022-03)。
文摘Due to the complicated film formation kinetics, morphology control remains a major challenge for the development of efficient and stable all-polymer solar cells(all-PSCs). To overcome this obstacle, the sequential deposition method is used to fabricate the photoactive layers of all-PSCs comprising a polymer donor PTzBI-oF and a polymer acceptor PS1. The film morphology can be manipulated by incorporating amounts of a dibenzyl ether additive into the PS1 layer. Detailed morphology investigations by grazing incidence wide-angle X-ray scattering and a transmission electron microscope reveal that the combination merits of sequential deposition and DBE additive can render favorable crystalline properties as well as phase separation for PTzBI-oF:PS1 blends. Consequently, the optimized all-PSCs delivered an enhanced power conversion efficiency(PCE) of 15.21%along with improved carrier extraction and suppressed charge recombination. More importantly, the optimized all-PSCs remain over 90% of their initial PCEs under continuous thermal stress at 65 °C for over 500 h. This work validates that control over microstructure morphology via a sequential deposition process is a promising strategy for fabricating highly efficient and stable all-PSCs.
基金the National Natural Science Foundation of China (NSFC) (51673092, 51973087 and 21762029) for financial support。
文摘Polymer acceptors based on extended fused ring p skeleton has been proven to be promising candidates for all-polymer solar cells(all-PSCs), due to their remarkable improved light absorption than the traditional imide-based polymer acceptors. To expand structural diversity of the polymer acceptors, herein,two polymer acceptors PSF-IDIC and PSi-IDIC with extended fused ring p skeleton are developed by copolymerization of 2,20-((2 Z,20 Z)-((4,4,9,9-tetrahexadecyl-4,9-dihydro-s-indaceno [1,2-b:5,6-b']dithio phene-2,7-diyl)bis(methanylylidene))bis(3-oxo-2,3-dihydro-1 H-indene-2,1-diylidene))dimalononitrile(IDIC-C16) block with sulfur(S) and fluorine(F) functionalized benzodithiophene(BDT) unit and silicon(Si) atom functionalized BDT unit, respectively. Both polymer acceptors exhibit strong light absorption.The PSF-IDIC exhibits similar energy levels and slightly higher absorption coefficient relative to the PSi-IDIC. After blended with the donor polymer PM6, the functional atoms on the polymer acceptors show quite different effect on the device performance. Both of the acceptors deliver a notably high open circuit voltage(V_(OC)) of the devices, but PSi-IDIC achieves higher V OCthan PSF-IDIC. All-PSC based on PM6:PSi-IDIC attains a power conversion efficiency(PCE) of 8.29%, while PM6:PSF-IDIC-based device achieves a much higher PCE of 10.18%, which is one of the highest values for the all-PSCs reported so far. The superior device performance of PM6:PSF-IDIC is attributed to its higher exciton dissociation and charge transport, decreased charge recombination, and optimized morphology than PM6:PSi-IDIC counterpart. These results suggest that optimizing the functional atoms of the side chain provide an effective strategy to develop high performance polymer acceptors for all-PSCs.
基金the Swedish Research Council (2016-06146,2019-02345)Swedish Research Council (grant no.2020-05223)+7 种基金the Swedish Research Council Formas,the Swedish Energy Agency (52473-1)the Wallenberg Foundation (2017.0186 and 2016.0059) for financial supportsupported by the National Research Foundation of Korea (NRF-2017M3A7B8065584 and 2020R1A4A1018516)Support from the National Natural Science Foundation of China (61774077)the Key Projects of Joint Fund of Basic and Applied Basic Research Fund of Guangdong Province (2019B1515120073)the Research Fund of Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology (No.2020B1212030010)Support from Sino-Danish Center for Education and ResearchSwedish Energy Agency (grant no.45420-1)
文摘All-polymer solar cells(all-PSCs)possess attractive merits including superior thermal stability and mechanical flexibility for large-area roll-to-roll processing.Introducing flexible conjugation-break spacers(FCBSs)into backbones of polymer donor(P_(D))or polymer acceptor(P_(A))has been demonstrated as an efficient approach to enhance both the photovoltaic(PV)and mechanical properties of the all-PSCs.However,length dependency of FCBS on certain all-PSC related properties has not been systematically explored.In this regard,we report a series of new non-conjugated P_(A)s by incorporating FCBS with various lengths(2,4,and 8 carbon atoms in thioalkyl segments).Unlike com-mon studies on so-called side-chain engineering,where longer side chains would lead to better solubility of those resulting polymers,in this work,we observe that the solubilities and the resulting photovoltaic/mechanical properties are optimized by a proper FCBS length(i.e.,C2)in P_(A) named PYTS-C2.Its all-PSC achieves a high efficiency of 11.37%,and excellent mechanical robustness with a crack onset strain of 12.39%,significantly superior to those of the other P_(A)s.These results firstly demonstrate the effects of FCBS lengths on the PV performance and mechanical properties of the all-PSCs,providing an effective strategy to fine-tune the structures of P_(A)s for highly efficient and mechanically robust PSCs.
基金financial support by the "Thousand Talents Program for Young Scholars" of China
文摘In recent years, a large library of n-type polymers have been developed and widely used as acceptor materials to replace fullerene derivatives in polymer solar cells(PSCs), stimulating the rapid expansion of research on so-called all-polymer solar cells(a PSCs). In particular, rylene diimide-based n-type polymer acceptors have attracted broad research interest due to their high electron mobility, suitable energy levels, and strong light-harvesting ability in the visible region. Among various polymer acceptors, rylene diimide-based polymers presented best performances when served as the acceptor materials in a PSCs. Typically, a record power conversion efficiency(PCE) of 7.7% was very recently achieved from an a PSC with a rylene diimide polymer derivative as the acceptor component. In this review, we highlight recent progress of n-type polymers originated from two significant classes of rylene diimide units, namely naphthalene diimide(NDI) and perylene diimide(PDI), as well as their derivatives for a PSC applications.
基金the financial supports from the Department of Science and Technology of Inner Mongolia (No. 2020GG0192)the Natural Science Foundation of Inner Mongolia (No. 2022ZD04)the Inner Mongolia Normal University (No. 112/1004031962)。
文摘A-DA'D-A type polymerized small-molecule acceptors(PSMAs) have very recently received wide attention because they possess advantages such as synthetic flexibility, narrowed bandgap, low energy loss, and impressive mechanical properties. With efforts on design and synthesis of PSMAs and polymer donors, significant progress has been made on all polymer solar cells(allPSCs) with power conversion efficiencies exceeding 18%. In this review, we focus on structure-property-performance relationships of the A-DA'D-A type PSMAs. First, we in-depth review the regio-random, regio-regular, and random ternary series by focusing on their structural modification such as from aspects of side-chains, halogenation, selenophene-containing and linkers, respectively. Second, we review the mechanically flexible and stretchable properties, which helps to find structural gene that correlates the mechanical properties. Third, we review the impressive small energy loss. In all, this review provides structural and material's clues, helpfully for designing high-performance all-PSCs.
基金supported by the Ministry of Science and Technology of China(2019YFA0705900)the National Natural Science Foundation of China(21875072,22275058,and U20A6002)Guangdong Innovative and Entrepreneurial Research Team Program(2019ZT08L075).
文摘Comprehensive Summary The regioregularity induced by the isomers of the end-groups has been widely recognized as a key factor that determines the photovoltaic properties of polymerized small molecular acceptors(PSMAs)in all-polymer solar cells(all-PSCs).However,the influence of regioregularity on the photovoltaic properties of non-fused PSMAs has not been explored yet.In this contribution,two regioregular non-fused PSMAs,PFBTz-T-γand PFBTz-T-δ,were synthesized for the first time by using the monomers with isomeric pure end-groups.Compared with PFBTz-T-δ,PFBTz-T-γhas more compact and more ordered packing in solid state,which results in a more red-shifted optical absorption and a higher electron mobility.More remarkably,PFBTz-T-γand PFBTz-T-δexhibited huge difference in photovoltaic performance in all-PSCs,which offered the power conversion efficiencies(PCEs)of 9.72%and 0.52%,respectively.Further studies have unveiled that the higher PCE of PFBTz-T-γis due to more efficient exciton dissociation,higher and more balanced electron/hole mobility,and less charge recombination as a result of favorable morphology of the blend film.This work demonstrates that the development of regioregular non-fused PSMAs by tuning the polymerization sites is an effective strategy for obtaining high-efficiency all-PSCs.
基金supported by the National Natural Science Foundation of China(22075200,52121002)the Fundamental Research Funds for the Central Universities。
文摘P3HT stands out from numerous polymer donors owing to the merits of low cost and high scalability of synthesis.However,the photovoltaic performance of P3HT-based blends lags significantly behind the state-of-the-art systems,especially for all-polymer solar cells(APSCs) that generally show efficiency of around 3%–4% due to the lack of matched polymer acceptors.Herein,a polymer acceptor,named IDTBTC8-CN,was designed and synthesized with indacenodithiophene(IDT) and mono-cyano(CN)-substituted benzothiadiazole(BT-CN) as building blocks.Introducing a CN group endowed the polymer with decreased bandgap,and apparent n-type charge transport character despite the relatively high energy levels.Additionally,IDTBTC8-CN showed largely improved miscibility with P3HT,compared with that of BT-based control polymer IDTBTC8.The high miscibility between P3HT and IDTBTC8-CN as well as the amorphous aggregation behavior of IDTBTC8-CN enabled a broad manipulation room for the blend film to acquire favorable morphology.Eventually,a champion efficiency of 8.30% was achieved,in sharp contrast to that of the IDTBTC8-based system(1.21%).Such efficiency is a new record for P3HT-based APSCs reported so far.Moreover,P3HT:IDTBTC8-CN blend film also exhibited excellent mechanical robustness.This study implies the guidance of molecular design of the polymer acceptors and morphology control for P3HT-based APSCs.
基金supported by National Natural Science Foundation of China(NSFC)(No.51973146)Shandong Provincial Natural Science Foundation(ZR2022JQ09)。
文摘Narrow-bandgap n-type polymers are essential for advancing the development of all-polymer solar cells(all-PSCs).Herein,we developed a novel polymer acceptor PNT withπ-extended 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile(CPNM)end groups.Compared to commonly used 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1ylidene)malononitrile(IC)units,CPNM units have a further extended fused ring,providing the PNT polymer with extended absorption into the near-IR region(903 nm)and exhibiting a narrow optical bandgap(1.37 eV).Furthermore,PNT exhibits a high electron mobility(6.79×10^(−4) cm^(2)·V^(−1)·S^(−1))and a relatively high-lying lowest unoccupied molecular orbital(LUMO)energy level of−3.80 eV.When blended with PBDB-T,all-PSC achieves a power conversion efficiency(PCE)of 13.7%and a high short-circuit current density(JSC)of 24.4 mA·cm^(−2),mainly attributed to broad absorption(600—900 nm)and efficient charge separation and collection.Our study provides a promising polymer acceptor for all-PSCs and demonstrates thatπ-extended CPNM units are important to achieve high-performance for all-PSCs.
基金supported by the National Natural Science Foundation of China (51973146)the Shandong Provincial Natural Science Foundation (ZR2022JQ09)the Collaborative Innovation Center of Suzhou Nano Science & Technology。
文摘The development of polymerized fused-ring small molecule acceptors(FRA-PAs) has boosted the performance of all-polymer solar cells(all-PSCs).However,these FRA-PAs suffer from lengthy synthesis steps and high production costs due to the high degree of synthetic complexity for fused-ring small molecule acceptors(FRAs).Furthermore,most FRA-PAs exhibit strong batch-to-batch variation,limiting further industrial applications.Herein,we designed and synthesized asymmetric non-fused electron-deficient building block TIC-Br with a simple structure(only three synthetic steps),showing a planar configuration,excellent electron affinity,and large dipole moment.A simple polymer acceptor PTIB was further developed by polymerization of TIC-Br and sensitized fluorinated-thienyl benzodithiophene(BDT-TF-Sn).PTIB exhibits a broad absorption from 300 to 800 nm,a suitable lowest unoccupied molecular orbital(LUMO) energy level of-3.86 e V,and moderate electron mobility(1.02×10^(-4)cm^(2)V^(-1)s^(-1)).When matched with PM6,the device achieved the best PCE of 10.11%with a high V_(OC) of 0.97 V,which is one of the highest among those reported all-PSCs.More importantly,PTIB exhibits a lower synthetic complexity index(SC=35.0%)and higher figure-of-merit values(FOM=29.0%) than all the reported high-performance PAs.The polymer also exhibits excellent batch-to-batch reproducibility and great potential for scale-up fabrication.This study indicates that TIC-Br is a promising building block for constructing low-cost polymer acceptors for large-scale applications in all-PSCs.
基金supported by the National Natural Science Foundation of China(Nos.52130306,22075287 and 22101285)the Nature Science Foundation of Fujian Province(No.2021J01515)the Program of Youth Innovation Promotion Association CAS(No.2021299).
文摘One important subject in the field of all-polymer solar cells (all-PSCs) is the exploration of electron-deficient building blocks with optimized physicochemical properties to promote the performance of polymer acceptors. Here, two ladder-type heteroheptacene-containing small-molecule acceptors with branched 2-octyldodecyl or 2-hexyldecyl side-chains are synthesized and polymerized with the thiophene co-monomer to afford polymer acceptors (PW-OD and PW-HD) with strong near-infrared absorption. Experimental results reveal that the alkyl chain length has a large impact on the molecular packing behavior of the resulting polymers, which in turn affects their light-absorbing and charge transport properties, and thus the photovoltaic performance of the final devices. When blended with the polymer donor PM6, PW-HD-based all-PSCs deliver a higher power conversion efficiency (PCE) of 9.12% compared to the PCE of 6.47% for the PW-OD-based all-PSCs, mainly due to its more ordered inter-chain packing and more favorable blend morphology. This work provides a promising building block for the development of high-performance narrow-bandgap polymer acceptors and highlights the importance of side-chain substitution in optimizing the photovoltaic performance of polymer acceptors.
基金financially supported by the National Natural Science Foundation of China(Nos.61904181,51820105003,52173188 and 21734008)the Basic and Applied Basic Research Major Program of Guangdong Province(No.2019B030302007)。
文摘The active layer of all polymer solar cells(all-PSCs)is composed of a blend of a p-type conjugated polymer(p-CP)as donor and an n-type conjugated polymer(n-CP)as acceptor.All-PSCs possess the advantages of light weight,thin active layer,mechanical flexibility,low cost solution processing and high stability,but the power conversion efficiency(PCE)of the all-PSCs was limited by the poor photovoltaic performance of the n-CP acceptors before 2016.Since the report of the strategy of polymerized small molecule acceptors(PSMAs)in 2017,the photovoltaic performance of the PSMA-based n-CPs improved rapidly,benefitted from the development of the A-DA’D-A type small molecule acceptors(SMAs).PCE of the all-PSCs based on the PSMA acceptors reached 17%-18%recently.In this review article,we will introduce the development history of the n-CPs,especially the recent research progress of the PSMAs.Particularly,the structure-property relationship of the PSMAs is introduced and discussed.Finally,current challenges and prospects of the n-CP acceptors are analyzed and discussed.
基金We acknowledge financial support provided by the National Natural Science Foundation of China(Nos.21822503 and 51973043)the and the CAS-CSIRO Joint Project of Chinese Academy of Sciences(No.121E32KYSB20190021).
文摘The stability issue is one of the key factors hindering the commercial application of organic solar cells.All-polymer organic solar cell is one of the effective ways to solve the stability problem.In this work,we designed and synthesized two polymer donor materials PBDT and PDTBDT with different conjugation ranges,and demonstrated for the first time that extending the conjugation range of donor materials in all polymer solar cells can significantly improve device efficiency and stability.The experimental results of materials and devices show that PDTBDT with a larger conjugation range has stronger crystallinity and a more planar structure,which endows the active layer in its corresponding device with higher exciton dissociation probability,lower carrier recombination probability,more balanced charge transport properties and more favorable film morphology.As a result,the PDTBDT:PYF-T-o devices display an outstanding PCE of 13.38%,which is much higher than PBDT with smaller conjugation range based devices.Moreover,the PDTBDT:PYF-T-o device retains 0.86 of the initial PCE after over 500 h in the air atmosphere,exhibiting significantly improved stability.The improved stability is attributed to the enhanced moisture and air tolerance of active layer film thanks to the strong crystallinity of the donor material.These results demonstrate that the conjugation expansion strategy is one of the effective ways to obtain efficient and stable all-polymer organic solar cells.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.52073068,22135001,and 21721002)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB36000000).
文摘The slot-die coating is recognized as the most compatible method for the roll-to-roll(R2R)processing of large-area flexible organic solar cells(OSCs).However,the photovoltaic performance of the large-area flexible all-polymer solar cells was significantly lagging behind that of polymer donors with small molecule non-fullerene acceptors devices.In this work,the 1 cm^(2) flexible device of an all-polymer system,PTQ10:PYF-T-o,fabricated by slot-die coating,achieves an excellent efficiency of 11.24%via controlling the coating temperatures.It is found that,compared with the donor,the crystallinity of PYF-T-o plays a crucial role in device performance.The all-polymer flexible devices show superior mechanical bending stability,maintaining an efficiency of over 95%of the initial value during a 1000-cycle bending test.
基金supported by the National Natural Science Foundation of China(Nos.21822505,91633301,51673069,and 21520102006)Program for Science and Technology Development of Dongguan(No.2019622163009)+1 种基金the Dongguan Innovative Research Team Program(No.2018607201002)Portions of this research used the resources of beamline 7.3.3 and 11.0.1.2 at Advanced Light Source,Materials Science Division,The Molecular Foundry,Lawrenee Berkeley National Laboratory,which was supported by the Office of Scienee,Office of Basic Energy Sciences,of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231.
文摘Adva nces in orga nic photovoltaic tech no logies have been geared toward industrial high-throughput printing manufacturing,which requires in sensitivity of photovoltaic performance reg a rd i ng to the light-harvesting layer thickness.However,the thickness of light-harvesti ng layer for all polymer solar cells(all-PSCs)is often limited to about 100 nm due to the dramatically decreased fill factor upon increasing film thickness,which hampers the light harvesting capability to in crease the power con versio n efficie ncy,and is un favorable for fabricating large-area devices.Here we dem on strate that by tuning the bulk heterojuncti on morphology using a non-halogenated solvent,cyclopentyl methyl ether,in the presence of a gree n solve nt additive of dibenzyl ether,the power con versio n efficie ncy of all-PSCs with photoactive layer thick nesses of over 500 nm reached an impressively high value of 9%.The gen eric applicability of this gree n solvent additive to boost the power conversion efficiency of thick-film devices is also validated in various bulk heterojunction active layer systems,thus representing a promising approach for the fabrication of all-PSCs toward industrial production,as well as further commercialization.
基金This work was supported by the Swedish Research Council(2015-04853,2016-06146,2019-04683)the Swedish Research Council Formas,the Knut and Alice Wallenberg Foundation(2017.0186,2016.0059)+5 种基金the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology,2020-skllmd-07)E.Moons thanks the Swedish Energy Council for financial support(project 48598-1)W.Su thanks the project funded by China Postdoctoral Science Foundation(2020M673054)Postdoctoral Fund of Jinan University,and the National Natural Science Foundation of China(22005121)L.Hou thanks the National Natural Science Foundation of China(61774077)Support from Sino-Danish Centre for Education and Research is fully acknowledged by D.Yu.Y.Li thanks the financial support from the Science and Technology Program of Shanxi Province(2019JQ-244).
文摘The non-fully conjugated polymer as a new class of acceptor materials has shown some advantages over its small molecular counterpart when used in photoactive layers for all-polymer solar cells(all-PSCs),despite a low power conversion efficiency(PCE)caused by its narrow absorption spectra.Herein,a novel non-fully conjugated polymer acceptor PFY-2TS with a low bandgap of~1.40 eV was developed,via polymerizing a largeπ-fused small molecule acceptor(SMA)building block(namely YBO)with a non-conjugated thioalkyl linkage.Compared with its precursor YBO,PFY-2TS retains a similar low bandgap but a higher LUMO level.Moreover,compared with the structural analog of YBO-based fully conjugated polymer acceptor PFY-DTC,PFY-2TS shows a similar absorption spectrum and electron mobility,but significantly different molecular crystallinity and aggregation properties,which results in optimal blend morphology with a polymer donor PBDB-T and physical processes of the device in all-PSCs.As a result,PFY-2TS-based all-PSCs achieved a PCE of 12.31%with a small energy loss of 0.56 eV enabled by the reduced non-radiative energy loss(0.24 eV),which is better than that of 11.08%for the PFY-DTC-based ones.Our work clearly demonstrated that non-fully conjugated polymers as a new class of acceptor materials are very promising for the development of high-performance all-PSCs.
基金supported by the Ministry of Science and Technology of China(2019YFA0705900)the National Natural Science Foundation of China(21875072)+2 种基金the Fundamental Research Funds for the Central Universities(South China University of Technology,D2190310)Guangdong Innovative and Entrepreneurial Research Team Program(2019ZT08L075)the Open Funds of State Key Laboratory of Fine Chemicals(KF1901)。
文摘We report all-polymer solar cells(All-PSCs) with record-high power conversion efficiency(PCE) through tuning the molecular weights of the polymer donor(PBDB-T) to form optimal active layer morphology. By combining the polymer donors with a newly reported polymer acceptor(PJ1), an unprecedented high PCE of 15.4% and fill factor over 75% were achieved for the AllPSCs with the medium molecular weight polymer donor(PBDB-TMW), which is the highest value for All-PSCs reported so far.Detailed morphology investigation revealed that the proper phase separation in the PBDB-TMW:PJ1 blend should account for the superior device performance as PBDB-TMW exhibits appropriate miscibility with the polymer acceptor PJ1. These results demonstrated that the device performance of All-PSCs could be fully comparable to that of small molecular acceptor-based PSCs. The formation of optimized morphology via precise control of molecular weights of polymer donors and acceptors is crucial to achieve this goal.
文摘Bulk-heterojunction polymer solar cells(PSCs)have attracted considerable attention owning to their potential for fabricating flexible,light-weight and large area solar cell panels via high-throughput roll-to-roll technologies.Compared with conventional PSCs comprising small molecule acceptors,such as fullerenes,all-polymer solar cells(all-PSCs)containing blends of p-type/n-type polymers in the photoactive layer provide advantages including
基金supported by the APRC Grant of the City University of Hong Kong(9380086)Innovation and Technology Fund(ITS/497/18FP,GHP/021/18SZ)+7 种基金the Office of Naval Research(N00014-201-2191)the GRF grant(11307621)from the Research Grants Council of Hong Kongthe National Natural Science Foundation of China(21905103)the Natural Science Foundation of Guangdong Province(2019A1515010761,2019A1515011131)Guangdong Major Project of Basic and Applied Basic Research(2019B030302007)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials(2019B121205002)the Fundamental Research(Discipline Arrangement)Project funding from the Shenzhen Science and Technology Innovation Committee(JCYJ20180507181718203)US Office of Naval Research Contract N0001420-1-2116 for support。
文摘Despite the significant progress made recently in all-polymer solar cells(all-PSCs),it is still quite challenging to achieve high open-circuit voltage(V_(oc))and short-circuit current density(J_(sc))simultaneously in order to further improve their performance.The recent strategy of using selenophene to replace thiophene on the Y6 based polymer acceptors has resulted in significantly improved J_(sc)s of the resulting all-PSCs.However,such modifications have also depressed V_(oc),which compromises the overall performance of the devices.Herein,we present the design and synthesis of a novel polymer acceptor,PYT-1S1Se,created by inserting an asymmetrical selenophene-fused framework to precisely manipulate optical absorption and electronic properties.Compared with the selenium-free analog,PYT-2S,and symmetrical selenium-fused analog,PYT-2Se,the PYT-1S1Se derived all-PSCs not only deliver optimized J_(sc)(24.1 mA cm^(−2))and V_(oc)(0.926 V)metrics,but also exhibit a relatively low energy loss of 0.502 eV.Consequently,these devices obtain a record-high power conversion efficiency(PCE)of 16.3%in binary all-PSCs.This work demonstrates an effective molecular design strategy for balancing the trade-off between V_(oc) and J_(sc) to achieve highefficiency all-PSCs.
基金Guo X is grateful to the Shenzhen Science and Technology Innovation Commission(JCYJ20170817105905899,JCYJ20180504165709042)Sun H thanks the National Natural Science Foundation of China(21801124)+3 种基金Liu B thanks China Scholarship Council Fund(201906010074)This work was supported by the National Natural Science Foundation of China(21903017)the Center for Computational Science and Engineering of Southern University of Science and Technology(SUSTech)We thank Ziang Wu and Han Young Woo at Korea University for performing GIWAXS measurements,thank Dr.Yinhua Yang at the Materials Characterization and Preparation Center,SUSTech for NMR measurement.
文摘The open-circuit voltage(Voc) of all-polymer solar cells(all-PSCs) is typically lower than 0.9 V even for the most efficient ones.Large energy loss is the main reason for limiting Voc and efficiency of all-PSCs. Herein, through materials design using electron deficient building blocks based on bithiophene imides, the lowest unoccupied molecular orbital(LUMO) energy levels of polymer acceptors can be effectively tuned, which resulted in a reduced energy loss induced by charge generation and recombination loss due to the suppressed charge-transfer(CT) state absorption. Despite a negligible driving force, all-PSC based on the polymer donor and acceptor combination with well-aligned energy levels exhibited efficient charge transfer and achieved an external quantum efficiency over 70% while maintaining a large Voc of 1.02 V, leading to a 9.21% efficiency. Through various spectroscopy approaches, this work sheds light on the mechanism of energy loss in all-PSCs, which paves an avenue to achieving efficient all-PSCs with large Voc and drives the further development of all-PSCs.