Low-cost photovoltaic materials are essential for realizing large-scale commercial applications of organic solar cells(OSCs).However,highly efficient OSCs based on low-cost photovoltaic materials are scarce due to a d...Low-cost photovoltaic materials are essential for realizing large-scale commercial applications of organic solar cells(OSCs).However,highly efficient OSCs based on low-cost photovoltaic materials are scarce due to a deficiency in understanding the structure-property relationship.Herein,we investigated two low-cost terthiophene-based electron acceptors,namely,3TC8 and 3TEH,with 3,4-bis(octan-3-yloxy)thiophene,differing only in the alkylated thiophene-bridges.Both acceptors exhibit low optical gaps(∼1.43 eV)and possess deep highest occupied molecular orbital(HOMO)levels(∼−5.8 eV).Notably,the single-crystal structure of 3TEH demonstrates highly planar conjugated backbone and strongπ-πstacking between intermolecular terminal groups,attributed to the presence of the bulky alkylated noncovalently conformational locks.Upon utilizing both acceptors to fabricate OSCs,the 3TC8-based device exhibited a power conversion efficiency(PCE)of 11.1%,while the 3TEH-based OSC demonstrated an excellent PCE of 14.4%.This PCE is the highest among OSCs based on terthiophene-containing electron acceptors.These results offer a new strategy for designing low-cost electron acceptors for highly efficient OSCs.展开更多
Developing narrow-bandgap organic semiconductors is important to facilitate the advancement of organic photovoltaics(OPVs). Herein, two near-infrared non-fused ring acceptors(NIR NFRAs), PTBFTT-F and PTBFTT-Cl have be...Developing narrow-bandgap organic semiconductors is important to facilitate the advancement of organic photovoltaics(OPVs). Herein, two near-infrared non-fused ring acceptors(NIR NFRAs), PTBFTT-F and PTBFTT-Cl have been developed with A-π_A-π_D-D-π_D-π_A-A non-fused structures. It is revealed that the introduction of electron deficient π-bridge(π_A) and multiple intramolecular noncovalent interactions effectively retained the structural planarity and intramolecular charge transfer of NFRAs, extending strong NIR photon absorption up to 950 nm. Further, the chlorinated acceptor, with the enlarged π-surface compared to the fluorinated counterpart, promoted not only molecular stacking in solid, but also the desirable photochemical stability in ambient, which are helpful to thereby improve the exciton and charge dynamics for the corresponding OPVs. Overall, this work provides valuable insights into the design of NIR organic semiconductors.展开更多
Fullerenes and their derivatives are important types of electron acceptor materials and play a vital role in organic solar cell devices. However, the fullerene acceptor material has some difficulties to overcome the i...Fullerenes and their derivatives are important types of electron acceptor materials and play a vital role in organic solar cell devices. However, the fullerene acceptor material has some difficulties to overcome the intrinsic shortcomings, such as weak absorption in the visible range, difficulty in modification and high cost, which limit the performance of the device and the large-scale application of this type of acceptors. In recent years, non-fullerene electron acceptor material has attracted the attention of scientists due to the advantages of adjustable energy level, wide absorption, simple synthesis, low processing cost and good solubility. Researchers can use the rich chemical means to design and synthesize organic small molecules and their oligomers with specific aggregation morphology and excellent optoelectronic prop- erties. Great advances in the field of synthesis, device engineering, and device physics of non-fullerene acceptors have been achieved in the last few years. At present, non-fullerene small molecules based photovoltaic devices achieve the highest efficiency more than 13% and the efficiency gap between fullerenetype and non-fullerene-type photovoltaic devices is gradually narrowing. In this review, we explore recent progress of non-fullerene small molecule electron acceptors that have been developed and led to highefficiency photovoltaic devices and put forward the prospect of development in the future.展开更多
Non-fullerene polymer solar cells(NF-PSCs) have gained wide attention recently. Molecular design of non-fullerene electron acceptors effectively promotes the photovoltaic performance of NF-PSCs. However,molecular elec...Non-fullerene polymer solar cells(NF-PSCs) have gained wide attention recently. Molecular design of non-fullerene electron acceptors effectively promotes the photovoltaic performance of NF-PSCs. However,molecular electron acceptors with 2-dimensional(2 D) configuration and conjugation are seldom reported.Herein, we designed and synthesized a series of novel 2 D electron acceptors for efficient NF-PSCs. With rational optimization on the conjugated moieties in both vertical and horizontal direction, these 2 D electron acceptors showed appealing properties, such as good planarity, full-spectrum absorption, high absorption extinction coefficient, and proper blend morphology with donor polymer. A high PCE of 9.76%was achieved for photovoltaic devices with PBDB-T as the donor and these 2 D electron acceptors. It was also found the charge transfer between the conjugated moieties in two directions of these 2 D molecules contributes to the utilization of absorbed photos, resulting in an exceptional EQE of 87% at 730 nm. This work presents rational design guidelines of 2 D electron acceptors, which showed great promise to achieve high-performance non-fullerene polymer solar cells.展开更多
Characteristics of phosphorus removal bacteria were investigated by using three different types of electron acceptors, as well as the positive role of nitrite in phosphorus removal process. An (AO)2 SBR (anaerobic-aer...Characteristics of phosphorus removal bacteria were investigated by using three different types of electron acceptors, as well as the positive role of nitrite in phosphorus removal process. An (AO)2 SBR (anaerobic-aerobic-anoxic-aerobic sequencing batch reactor) was thereby employed to enrich denitrifying phosphorus removal bacteria for simultaneously removing phosphorus and nitrogen via anoxic phosphorus uptake. Ammonium oxidation was controlled at the first phase of the nitrification process. Nitrite-inhibition batch tests illustrated that nitrite was not an inhibitor to phosphorus uptake process, but served as an alternative electron acceptor to nitrate and oxygen if the concentration was under the inhibition level of 40mg NO2-N·L-1. It implied that in addition to the two well-accepted groups of phosphorus removal bacterium (one can only utilize oxygen as electron acceptor, P1, while the other can use both oxygen and nitrate as electron acceptor, P2), a new group of phosphorus removal bacterium P3, which could use oxygen, nitrate and nitrite as electron acceptor to take up phosphorus were identified in the test system. To understand (AO)2 SBR sludge better, the relative population of the different bacteria in this system, plus another A/O SBR sludge (seed sludge) were respectively estimated by the phosphorus uptake batch tests with either oxygen or nitrate or nitrite as electron acceptor. The results demonstrated that phosphorus removal capability of (AO)2 SBR sludge had a little degradation after A/O sludge was cultivated in the (AO)2 mode over a long period of time. However, denitrifying phosphorus removal bacteria (P2 and P3) was significantly enriched showed by the relative population of the three types of bacteria, which implied that energy for aeration and COD consumption could be reduced in theory.展开更多
Small molecule ladder-type heteroarenes IHBT-2F is designed and synthesized with strong electrondonating and molecular packing properties, where the central unit, fused thienobenzene-thienothiphene (IHBT), is attached...Small molecule ladder-type heteroarenes IHBT-2F is designed and synthesized with strong electrondonating and molecular packing properties, where the central unit, fused thienobenzene-thienothiphene (IHBT), is attached with the strong electron-deficient 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2FIC) as the end group. The counterpart IDBT-2F with indancenodibenzothiophene (IDBT) mainchain is sythesized for comparison, in which thieno[3,2-b]thiophene (TT) core of IHBT is replaced by benzene core. Relative to benzene-core IDBT-2F, TT-core IHBT-2F shows a much higher highest occupied molecular orbital energy level (IHBT-2F:-5.46 eV;IDBT-2F:-5.72 eV) and significantly redshifted absorption, due to the π-donor capability of the sulfur atom, the larger π-conjugation and stronger intermolecular π-π stacking. The as-cast organic solar cells (OSCs) based on blends of PTB7-Th donor and IHBT-2F acceptor without additional treatments exhibit power conversion efficiencies (PCEs) as high as 8.74%, which is much higher than that of PTB7-Th:IDBT-2F (6.73%).展开更多
By employing the asymmetric end-group engineering,an asymmetric nonfused-ring electron acceptor(NFREA)was designed and synthesized.Compared with the symmetric analogs(NoCA-17 and NoCA-18),NoCA-19 possesses broader lig...By employing the asymmetric end-group engineering,an asymmetric nonfused-ring electron acceptor(NFREA)was designed and synthesized.Compared with the symmetric analogs(NoCA-17 and NoCA-18),NoCA-19 possesses broader light absorption range,more coplanarπ-conjugated backbone,and appropriate crystallinity according to the experimental and theoretical results.The organic solar cells based on J52:NoCA-19 exhibited a power conversion efficiency as high as 12.26%,which is much higher than those of J52:NoCA-17(9.50%)and J52:NoCA-18(11.77%),mainly due to more efficient exciton dissociation,better and balanced charge mobility,suppressed recombination loss,shorter charge extraction time,longer charge carrier lifetimes,and more favorable blend film morphology.These findings demonstrate the great potential of asymmetric end-group engineering in exploring low-cost and high-performance NFREAs.展开更多
In this study,biochar(BC)derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride(g-C_(3)N_(4))to synthesize the BC/g-C_(3)N_(4)composite for the degradation of...In this study,biochar(BC)derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride(g-C_(3)N_(4))to synthesize the BC/g-C_(3)N_(4)composite for the degradation of the tetracycline(TC)antibiotic under visible light irradiation.The experimental results exhibit that the optimal feeding weight ratio of biochar/urea is 0.03:1 in BC/g-C_(3)N_(4)composite could show the best photocatalytic activity with the degradation rate of tetracycline is 83%in 100 min irradiation.The improvement of photocatalytic activity is mainly attributed to the following two points:(i)the strong bonding with π-π stacking between BC and g-C_(3)N_(4)make the photogenerated electrons of light-excited g-C_(3)N_(4)transfer to BC,quickly and improve the separation efficiency of carriers;(ii)the introduction of BC reduces the distance for photogenerated electrons to migrate to the surface and increases the specific surface area for providing more active sites.This study provides a sustainable,economical and promising method for the synthesis of photocatalytic materials their application to wastewater treatment.展开更多
The 52%energy of the solar radiation is contributed by near-infrared radiation(NIR,780-2500 nm).Therefore,the material design for the energy-saving smart window,which can effectively shield NIR and has acceptable visi...The 52%energy of the solar radiation is contributed by near-infrared radiation(NIR,780-2500 nm).Therefore,the material design for the energy-saving smart window,which can effectively shield NIR and has acceptable visible transmittance,is vital to save the energy consumed on the temperature control system.It is important to find a non-toxic stable material with excellent NIR-shielding ability and acceptable visible transmittance.The systematic first-principles study on Li_(x)Sn_(y)WO_(3)(x=0,0.33,0.66,and y=0,0.33)exhibits that the chemical stability is a positive correlation with the doping concentration.After doping,the Fermi-energy upshifts into the conduction band,and the material shows metal-like characteristics.Therefore,these structures Li_(x)Sn_(y)WO_(3)(except the structure with x=0.33 and y=0)show pronounced improvement of NIR shielding ability.Our results indicate that when x=0 and y=0.33,the material exhibits the strongest NIR-shielding ability,satisfying chemical stability,wide NIR-shielding range(780-2500 nm),and acceptable visible transmittance.This work provides a good choice for experimental study on NIR shielding material for the energy-saving window.展开更多
Reduced rate constants of photoinduced electron transfer in intramolecular fluorescence quenching of donor-acceptor podands induced by cation-complexation are observed in the highly exothermic reactions.
Photoinduced charge transfer polymerization of styrene(St) with electron acceptor as initiator was investigated. In case of fumaronitrile (FN) or maleic anhydride (MA) as initiator the polymerization takes place regul...Photoinduced charge transfer polymerization of styrene(St) with electron acceptor as initiator was investigated. In case of fumaronitrile (FN) or maleic anhydride (MA) as initiator the polymerization takes place regularly, whereas the tetrachloro-1,4-benzenequinone (TCQ), 2,3-dichloro-5, 6-dicyano-1, 4-benzenequinone (DDQ). or tetracyano ethylene (TCNE) as initiator the polymerization proceeds reluctantly only after the photoaddition reaction. A mechanism was proposed that free radicals would be formed following the charge and proton transfer in the exciplex formed between St and electron accepters.展开更多
Using depletion approximation theory and introducing acceptor defects which can characterize radiation induced deep-level defects in AlGaN/GaN heterostructures,we set up a radiation damage model of AlGaN/GaN high elec...Using depletion approximation theory and introducing acceptor defects which can characterize radiation induced deep-level defects in AlGaN/GaN heterostructures,we set up a radiation damage model of AlGaN/GaN high electron mobility transistor (HEMT) to separately simulate the effects of several main radiation damage mechanisms and the complete radiation damage effect simultaneously considering the degradation in mobility. Our calculated results,consistent with the experimental results,indicate that thin AlGaN barrier layer,high Al content and high doping concentration are favourable for restraining the shifts of threshold voltage in the AlGaN/GaN HEMT;when the acceptor concentration induced is less than 10^14cm-3,the shifts in threshold voltage are not obvious;only when the acceptor concentration induced is higher than 10^16cm-3,will the shifts of threshold voltage remarkably increase;the increase of threshold voltage,resulting from radiation induced acceptor,mainly contributes to the degradation in drain saturation current of the current-voltage (Ⅰ-Ⅴ) characteristic,but has no effect on the transconductance in the saturation area.展开更多
Synergistically achieving stability,cost,and efficiency is crucial for the commercialization of organic solar cells(OSCs).Despite the rapid development of 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malo nonitriletypenon ...Synergistically achieving stability,cost,and efficiency is crucial for the commercialization of organic solar cells(OSCs).Despite the rapid development of 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malo nonitriletypenon fullerene acceptors(NFAs),they areinherently unstable due to the vulnerable exocyclic double bond and possess high synthesis complexity(SC).Based on the“all-fused-ring electron acceptor(AFAR)”concept,we report two new near-infrared NFAs,F11 and F13,featuring all fused dodecacyclic rings.By developing a whole set of synthetic procedures,F11 and F13 can be conveniently prepared at a 10 g scale within a notably short period,displaying both the low SC and the lowest costs among reported NFAs,even comparable to the classical photovoltaic material,P3HT.In comparison with the one-dimensional stacking of ITYM(ITYM=2,2′-(7,7,15,15-tetrahexyl-7,15-dihydro-s-indaceno[1,2-b:5,6-b′]diindeno[1,2-d]thiophene-2,10(2H)-diylidene)dimalononitrile),the first AFRA,and mixed J-and H-aggregations in Y6,F-acceptors show a compact honeycomb-type three-dimensional stacking with exclusive J-aggregations,favoring multichannel charge transport.By matching a medium-bandgap polymer donor,F13 delivers greater than 13%power conversion efficiencies,which is the highest performance among non-INCN acceptors,and shows device stability superior to the typical ITIC-and Y6-based OSCs as evidenced by the negligible burn-in losses.This work presents a first and successful example of NFAs achieving an optimal efficiency-cost-stability balance in OSCs.展开更多
Nonfused ring electron acceptors(NFREAs)have attracted much attention due to their concise synthetic routes and low cost.However,developing high-performance NFREAs with simple structure remains a great challenge.In th...Nonfused ring electron acceptors(NFREAs)have attracted much attention due to their concise synthetic routes and low cost.However,developing high-performance NFREAs with simple structure remains a great challenge.In this work,a simple building block(POBT)with noncovalently conformational locks(No CLs)was designed and synthesized.Single-crystal X-ray study indicated the presence of S…O NOCLs in POBT,thus enabling it to possess a coplanar conformation comparable to that of fused-ring CPT.Two novel NFREAs based on CPT and POBT were developed,namely TT-CPT and TT-POBT,respectively.Besides,TT-POBT possessed a smaller Stokes shift and a reduced reorganization energy compared with TT-CPT,indicating the introduction of S…O No CLs can enhance the molecular rigidity even if simplifying the molecular structure.As a result,the TT-POBT-based PSC device afforded an impressive power conversion efficiency of 11.15%,much higher than that of TT-CPT counterpart(7.03%),mainly resulting from the tighterπ-πstacking,improved and balanced charge transport,and more favorable film morphology.This work demonstrates the potential of the simple building block POBT with No CLs towards constructing low-cost and highperformance NFREAs.展开更多
Comprehensive Summary By employing thiazole and 4-chlorothiazole as the A′units,two A-D-A′-D-A type nonfused-ring electron acceptors(NFREAs)Tz-H and Tz-Cl were designed and synthesized.Replacing thiazole in Tz-H wit...Comprehensive Summary By employing thiazole and 4-chlorothiazole as the A′units,two A-D-A′-D-A type nonfused-ring electron acceptors(NFREAs)Tz-H and Tz-Cl were designed and synthesized.Replacing thiazole in Tz-H with 4-chlorothiazole can not only remarkably shorten the synthetic route through C—H direct arylation but also enhance molecular planarity with the simultaneous incorporation of S…N and S…Cl noncovalently conformational locks(NoCLs).The photovoltaic devices based on PM6:Tz-Cl exhibited a power conversion efficiency as high as 11.10%,much higher than that of PM6:Tz-H(6.41%),mainly due to more efficient exciton dissociation,better and more balanced carrier mobility,less charge recombination,and more favorable morphology.These findings demonstrate the great potential of NoCLs in achieving low-cost and high-performance NFREAs.展开更多
Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the...Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the persistent radical anion(PRA)(possessing the properties of both radical and anion) was developed for NIR photocontrolled reversible additionfragmentation chain transfer(RAFT) polymerization,enabling successful polymerization while gaining a deep insight into the mechanism of photo-induced electron transfer RAFT(PET-RAFT) polymerization.Different from the conventional and wellaccepted reductive quenching(RQ) pathway,in which the radical anion intermediates of PCs(PCs^(·-)) must be generated in an excited state(ES),here,the PRA(3,4,9,10-perylenetetracarboxylic dianhydride radical anion(PTCDA^(·-))) could generate conveniently in situ in the ground state(GS) and subsequently serve as highly efficient PC in the NIR region(740–850 nm).The successful implementation of this strategy elucidates the peculiar role played by light and the real way of electron transfer behaviors.In fact,the transfer of a single electron from PRA to chain transfer agent(CTA) and cleavage of the C–S bonds is a process from ES to GS,rather than always from GS(PCs^(·-)) to GS(CTA) in the RQ pathway as is well known to all.In addition,the excellent spatial-temporal control and powerful penetration ability of the NIR light were also confirmed by this PRAcatalyzed polymerization system.展开更多
Near-infrared(NIR)phosphor-converted light-emitting diodes/laser diodes(LEDs/LDs)are prospective lighting sources for NIR spectroscopy.However,developing NIR phosphor materials with desired thermal robustness and high...Near-infrared(NIR)phosphor-converted light-emitting diodes/laser diodes(LEDs/LDs)are prospective lighting sources for NIR spectroscopy.However,developing NIR phosphor materials with desired thermal robustness and high photoelectric efficiency is a crucial challenge for their applications.In this work,based on the cationic radius matching effect,a series of(Lu,Y)_(3)(Al,Sc,Cr)_(2)Al_(3)O_(12)NIR phosphor ceramics(LuYScCr NIR-PCs)were fabricated by vacuum sintering.Excellent thermal stability(95%@150℃)was obtained in the prepared NIR-PCs,owing to their weak electron-phonon coupling effect(small Huang-Rhys factor).Being excited at 460 nm,NIR-PCs realized a broadband emission(650-850 nm)with internal quantum efficiency(IQE)of 60.68%.Combining NIR-PCs with LED/LD chips,the maximum output power of the encapsulated LED prototype was 447 mW@300 mA with photoelectric efficiency of as high as 18.6%@180 mA,and the maximum output power of the LD prototype was 814 mW@2.5 A.The working temperatures of NIR-PCs were 70.8℃@300 mA(LED)and 102.8℃@3 A(LD).Finally,the prepared NIR-PCs applied in food detection were verified in this study,demonstrating their anticipated application prospects in the future.展开更多
基金supported by the Beijing Natural Science Foundation of China(Z230019,2212005)the National Natural Science Foundation of China(NSFC 22173062,21833005,22090022 and 22275125).
文摘Low-cost photovoltaic materials are essential for realizing large-scale commercial applications of organic solar cells(OSCs).However,highly efficient OSCs based on low-cost photovoltaic materials are scarce due to a deficiency in understanding the structure-property relationship.Herein,we investigated two low-cost terthiophene-based electron acceptors,namely,3TC8 and 3TEH,with 3,4-bis(octan-3-yloxy)thiophene,differing only in the alkylated thiophene-bridges.Both acceptors exhibit low optical gaps(∼1.43 eV)and possess deep highest occupied molecular orbital(HOMO)levels(∼−5.8 eV).Notably,the single-crystal structure of 3TEH demonstrates highly planar conjugated backbone and strongπ-πstacking between intermolecular terminal groups,attributed to the presence of the bulky alkylated noncovalently conformational locks.Upon utilizing both acceptors to fabricate OSCs,the 3TC8-based device exhibited a power conversion efficiency(PCE)of 11.1%,while the 3TEH-based OSC demonstrated an excellent PCE of 14.4%.This PCE is the highest among OSCs based on terthiophene-containing electron acceptors.These results offer a new strategy for designing low-cost electron acceptors for highly efficient OSCs.
基金funded by National Natural Science Foundation of China (No.22125901)the National Key Research and Development Program of China (No.2019YFA0705900)the Fundamental Research Funds for the Central Universities (No.226–2023–00113)。
文摘Developing narrow-bandgap organic semiconductors is important to facilitate the advancement of organic photovoltaics(OPVs). Herein, two near-infrared non-fused ring acceptors(NIR NFRAs), PTBFTT-F and PTBFTT-Cl have been developed with A-π_A-π_D-D-π_D-π_A-A non-fused structures. It is revealed that the introduction of electron deficient π-bridge(π_A) and multiple intramolecular noncovalent interactions effectively retained the structural planarity and intramolecular charge transfer of NFRAs, extending strong NIR photon absorption up to 950 nm. Further, the chlorinated acceptor, with the enlarged π-surface compared to the fluorinated counterpart, promoted not only molecular stacking in solid, but also the desirable photochemical stability in ambient, which are helpful to thereby improve the exciton and charge dynamics for the corresponding OPVs. Overall, this work provides valuable insights into the design of NIR organic semiconductors.
基金the financial support by the National Natural Science Foundation of China(51303099)the Natural Science Basic Research Plan in Shaanxi Province of China(2017JM5058)the Funded Projects for the Academic Leaders and Academic Backbones,Shaanxi Normal University(16QNGG008)
文摘Fullerenes and their derivatives are important types of electron acceptor materials and play a vital role in organic solar cell devices. However, the fullerene acceptor material has some difficulties to overcome the intrinsic shortcomings, such as weak absorption in the visible range, difficulty in modification and high cost, which limit the performance of the device and the large-scale application of this type of acceptors. In recent years, non-fullerene electron acceptor material has attracted the attention of scientists due to the advantages of adjustable energy level, wide absorption, simple synthesis, low processing cost and good solubility. Researchers can use the rich chemical means to design and synthesize organic small molecules and their oligomers with specific aggregation morphology and excellent optoelectronic prop- erties. Great advances in the field of synthesis, device engineering, and device physics of non-fullerene acceptors have been achieved in the last few years. At present, non-fullerene small molecules based photovoltaic devices achieve the highest efficiency more than 13% and the efficiency gap between fullerenetype and non-fullerene-type photovoltaic devices is gradually narrowing. In this review, we explore recent progress of non-fullerene small molecule electron acceptors that have been developed and led to highefficiency photovoltaic devices and put forward the prospect of development in the future.
基金financially supported by the National Key Research and Development Program of China (No. 2019YFA0705900) funded by MOSTthe Basic and Applied Basic Research Major Program of Guangdong Province (No. 2019B030302007)the National Natural Science Foundation of China (No. 51521002)。
文摘Non-fullerene polymer solar cells(NF-PSCs) have gained wide attention recently. Molecular design of non-fullerene electron acceptors effectively promotes the photovoltaic performance of NF-PSCs. However,molecular electron acceptors with 2-dimensional(2 D) configuration and conjugation are seldom reported.Herein, we designed and synthesized a series of novel 2 D electron acceptors for efficient NF-PSCs. With rational optimization on the conjugated moieties in both vertical and horizontal direction, these 2 D electron acceptors showed appealing properties, such as good planarity, full-spectrum absorption, high absorption extinction coefficient, and proper blend morphology with donor polymer. A high PCE of 9.76%was achieved for photovoltaic devices with PBDB-T as the donor and these 2 D electron acceptors. It was also found the charge transfer between the conjugated moieties in two directions of these 2 D molecules contributes to the utilization of absorbed photos, resulting in an exceptional EQE of 87% at 730 nm. This work presents rational design guidelines of 2 D electron acceptors, which showed great promise to achieve high-performance non-fullerene polymer solar cells.
文摘Characteristics of phosphorus removal bacteria were investigated by using three different types of electron acceptors, as well as the positive role of nitrite in phosphorus removal process. An (AO)2 SBR (anaerobic-aerobic-anoxic-aerobic sequencing batch reactor) was thereby employed to enrich denitrifying phosphorus removal bacteria for simultaneously removing phosphorus and nitrogen via anoxic phosphorus uptake. Ammonium oxidation was controlled at the first phase of the nitrification process. Nitrite-inhibition batch tests illustrated that nitrite was not an inhibitor to phosphorus uptake process, but served as an alternative electron acceptor to nitrate and oxygen if the concentration was under the inhibition level of 40mg NO2-N·L-1. It implied that in addition to the two well-accepted groups of phosphorus removal bacterium (one can only utilize oxygen as electron acceptor, P1, while the other can use both oxygen and nitrate as electron acceptor, P2), a new group of phosphorus removal bacterium P3, which could use oxygen, nitrate and nitrite as electron acceptor to take up phosphorus were identified in the test system. To understand (AO)2 SBR sludge better, the relative population of the different bacteria in this system, plus another A/O SBR sludge (seed sludge) were respectively estimated by the phosphorus uptake batch tests with either oxygen or nitrate or nitrite as electron acceptor. The results demonstrated that phosphorus removal capability of (AO)2 SBR sludge had a little degradation after A/O sludge was cultivated in the (AO)2 mode over a long period of time. However, denitrifying phosphorus removal bacteria (P2 and P3) was significantly enriched showed by the relative population of the three types of bacteria, which implied that energy for aeration and COD consumption could be reduced in theory.
基金NSFC (21504058)NSFC/RGC Joint Research Scheme No. N_CUHK418/17+1 种基金Research Grant Council of Hong Kong (General Research Fund No. 14314216)the beam time and technical supports provided by 19U2 beamline at SSRF, Shanghai
文摘Small molecule ladder-type heteroarenes IHBT-2F is designed and synthesized with strong electrondonating and molecular packing properties, where the central unit, fused thienobenzene-thienothiphene (IHBT), is attached with the strong electron-deficient 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2FIC) as the end group. The counterpart IDBT-2F with indancenodibenzothiophene (IDBT) mainchain is sythesized for comparison, in which thieno[3,2-b]thiophene (TT) core of IHBT is replaced by benzene core. Relative to benzene-core IDBT-2F, TT-core IHBT-2F shows a much higher highest occupied molecular orbital energy level (IHBT-2F:-5.46 eV;IDBT-2F:-5.72 eV) and significantly redshifted absorption, due to the π-donor capability of the sulfur atom, the larger π-conjugation and stronger intermolecular π-π stacking. The as-cast organic solar cells (OSCs) based on blends of PTB7-Th donor and IHBT-2F acceptor without additional treatments exhibit power conversion efficiencies (PCEs) as high as 8.74%, which is much higher than that of PTB7-Th:IDBT-2F (6.73%).
基金the financial support fromtheNSFC(21975055,U2001222,52103352,52120105006,and 51925306)National Key R&D Program of China(2018FYA 0305800)+2 种基金Key Research Program of Chinese Academy of Sciences(XDPB08-2)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2022165)the Fundamental Research Funds for the Central Universities.DFT results described in this article were obtained from the National Supercomputing Centre in Shenzhen(Shenzhen Cloud Computing Centre).
文摘By employing the asymmetric end-group engineering,an asymmetric nonfused-ring electron acceptor(NFREA)was designed and synthesized.Compared with the symmetric analogs(NoCA-17 and NoCA-18),NoCA-19 possesses broader light absorption range,more coplanarπ-conjugated backbone,and appropriate crystallinity according to the experimental and theoretical results.The organic solar cells based on J52:NoCA-19 exhibited a power conversion efficiency as high as 12.26%,which is much higher than those of J52:NoCA-17(9.50%)and J52:NoCA-18(11.77%),mainly due to more efficient exciton dissociation,better and balanced charge mobility,suppressed recombination loss,shorter charge extraction time,longer charge carrier lifetimes,and more favorable blend film morphology.These findings demonstrate the great potential of asymmetric end-group engineering in exploring low-cost and high-performance NFREAs.
基金the founding support from the National Natural Science Foundation of China (21906072, 22006057 and 31971616)the Natural Science Foundation of Jiangsu Province (BK20190982)+4 种基金“Doctor of Mass Entrepreneurship and Innovation” Project in Jiangsu ProvinceHenan Postdoctoral Foundation (202003013)the Science and Technology Research Project of the Department of Education of Jilin Province (JJKH20200039KJ)the Science and Technology Research Project of Jilin City (20190104120, 201830811)the Project of Jilin Provincial Science and Technology Development Plan (20190201277JC, 20200301046RQ, YDZJ202101ZYTS070)
文摘In this study,biochar(BC)derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride(g-C_(3)N_(4))to synthesize the BC/g-C_(3)N_(4)composite for the degradation of the tetracycline(TC)antibiotic under visible light irradiation.The experimental results exhibit that the optimal feeding weight ratio of biochar/urea is 0.03:1 in BC/g-C_(3)N_(4)composite could show the best photocatalytic activity with the degradation rate of tetracycline is 83%in 100 min irradiation.The improvement of photocatalytic activity is mainly attributed to the following two points:(i)the strong bonding with π-π stacking between BC and g-C_(3)N_(4)make the photogenerated electrons of light-excited g-C_(3)N_(4)transfer to BC,quickly and improve the separation efficiency of carriers;(ii)the introduction of BC reduces the distance for photogenerated electrons to migrate to the surface and increases the specific surface area for providing more active sites.This study provides a sustainable,economical and promising method for the synthesis of photocatalytic materials their application to wastewater treatment.
文摘The 52%energy of the solar radiation is contributed by near-infrared radiation(NIR,780-2500 nm).Therefore,the material design for the energy-saving smart window,which can effectively shield NIR and has acceptable visible transmittance,is vital to save the energy consumed on the temperature control system.It is important to find a non-toxic stable material with excellent NIR-shielding ability and acceptable visible transmittance.The systematic first-principles study on Li_(x)Sn_(y)WO_(3)(x=0,0.33,0.66,and y=0,0.33)exhibits that the chemical stability is a positive correlation with the doping concentration.After doping,the Fermi-energy upshifts into the conduction band,and the material shows metal-like characteristics.Therefore,these structures Li_(x)Sn_(y)WO_(3)(except the structure with x=0.33 and y=0)show pronounced improvement of NIR shielding ability.Our results indicate that when x=0 and y=0.33,the material exhibits the strongest NIR-shielding ability,satisfying chemical stability,wide NIR-shielding range(780-2500 nm),and acceptable visible transmittance.This work provides a good choice for experimental study on NIR shielding material for the energy-saving window.
基金We are grateful to the National NatUral Science Foundation of China for support this work.!(grantNO. 29733100)
文摘Reduced rate constants of photoinduced electron transfer in intramolecular fluorescence quenching of donor-acceptor podands induced by cation-complexation are observed in the highly exothermic reactions.
文摘Photoinduced charge transfer polymerization of styrene(St) with electron acceptor as initiator was investigated. In case of fumaronitrile (FN) or maleic anhydride (MA) as initiator the polymerization takes place regularly, whereas the tetrachloro-1,4-benzenequinone (TCQ), 2,3-dichloro-5, 6-dicyano-1, 4-benzenequinone (DDQ). or tetracyano ethylene (TCNE) as initiator the polymerization proceeds reluctantly only after the photoaddition reaction. A mechanism was proposed that free radicals would be formed following the charge and proton transfer in the exciplex formed between St and electron accepters.
基金Project supported by the National Defense Scientific and Technical Pre-Research Program of China (Grant Nos 51311050112,51308040301 and 51308030102)the National Defense Fundamental Research Program of China (Grant No A1420060156)the National Basic Research Program of China (Grant No 513270407)
文摘Using depletion approximation theory and introducing acceptor defects which can characterize radiation induced deep-level defects in AlGaN/GaN heterostructures,we set up a radiation damage model of AlGaN/GaN high electron mobility transistor (HEMT) to separately simulate the effects of several main radiation damage mechanisms and the complete radiation damage effect simultaneously considering the degradation in mobility. Our calculated results,consistent with the experimental results,indicate that thin AlGaN barrier layer,high Al content and high doping concentration are favourable for restraining the shifts of threshold voltage in the AlGaN/GaN HEMT;when the acceptor concentration induced is less than 10^14cm-3,the shifts in threshold voltage are not obvious;only when the acceptor concentration induced is higher than 10^16cm-3,will the shifts of threshold voltage remarkably increase;the increase of threshold voltage,resulting from radiation induced acceptor,mainly contributes to the degradation in drain saturation current of the current-voltage (Ⅰ-Ⅴ) characteristic,but has no effect on the transconductance in the saturation area.
基金The authors thank the National Key R&D Program of China(grant nos.2019YFA0705900 and 2017YFA0204701)the National Natural Science Foundation of China(grant nos.22175187,91833304,21805289,and 22171273)+1 种基金Key Research Program of the Chinese Academy of Sciences(grant no.XDPB13)Youth Innovation Promotion Association CAS(grant no.2020031)for their financial support.
文摘Synergistically achieving stability,cost,and efficiency is crucial for the commercialization of organic solar cells(OSCs).Despite the rapid development of 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malo nonitriletypenon fullerene acceptors(NFAs),they areinherently unstable due to the vulnerable exocyclic double bond and possess high synthesis complexity(SC).Based on the“all-fused-ring electron acceptor(AFAR)”concept,we report two new near-infrared NFAs,F11 and F13,featuring all fused dodecacyclic rings.By developing a whole set of synthetic procedures,F11 and F13 can be conveniently prepared at a 10 g scale within a notably short period,displaying both the low SC and the lowest costs among reported NFAs,even comparable to the classical photovoltaic material,P3HT.In comparison with the one-dimensional stacking of ITYM(ITYM=2,2′-(7,7,15,15-tetrahexyl-7,15-dihydro-s-indaceno[1,2-b:5,6-b′]diindeno[1,2-d]thiophene-2,10(2H)-diylidene)dimalononitrile),the first AFRA,and mixed J-and H-aggregations in Y6,F-acceptors show a compact honeycomb-type three-dimensional stacking with exclusive J-aggregations,favoring multichannel charge transport.By matching a medium-bandgap polymer donor,F13 delivers greater than 13%power conversion efficiencies,which is the highest performance among non-INCN acceptors,and shows device stability superior to the typical ITIC-and Y6-based OSCs as evidenced by the negligible burn-in losses.This work presents a first and successful example of NFAs achieving an optimal efficiency-cost-stability balance in OSCs.
基金the National Natural Science Foundation of China(Nos.52103352,51925306 and 52120105006)National Key R&D Program of China(No.2018FYA 0305800)+3 种基金Key Research Program of Chinese Academy of Sciences(No.XDPB08-2)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB28000000)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2022165)the Fundamental Research Funds for the Central Universities.
文摘Nonfused ring electron acceptors(NFREAs)have attracted much attention due to their concise synthetic routes and low cost.However,developing high-performance NFREAs with simple structure remains a great challenge.In this work,a simple building block(POBT)with noncovalently conformational locks(No CLs)was designed and synthesized.Single-crystal X-ray study indicated the presence of S…O NOCLs in POBT,thus enabling it to possess a coplanar conformation comparable to that of fused-ring CPT.Two novel NFREAs based on CPT and POBT were developed,namely TT-CPT and TT-POBT,respectively.Besides,TT-POBT possessed a smaller Stokes shift and a reduced reorganization energy compared with TT-CPT,indicating the introduction of S…O No CLs can enhance the molecular rigidity even if simplifying the molecular structure.As a result,the TT-POBT-based PSC device afforded an impressive power conversion efficiency of 11.15%,much higher than that of TT-CPT counterpart(7.03%),mainly resulting from the tighterπ-πstacking,improved and balanced charge transport,and more favorable film morphology.This work demonstrates the potential of the simple building block POBT with No CLs towards constructing low-cost and highperformance NFREAs.
基金the National Natural Science Foundation of China((52120105006,52103352,and 51925306)National Key R&D Program of China(2018FYA 0305800)+3 种基金Key Research Program of Chinese Academy of Sciences(XDPB08-2)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB28000000)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2022165)the Fundamental Research Funds for the Central Universities.DFT results described in this report were obtained from the National Supercomputing Center in Shenzhen(Shenzhen CloudComputing Center).
文摘Comprehensive Summary By employing thiazole and 4-chlorothiazole as the A′units,two A-D-A′-D-A type nonfused-ring electron acceptors(NFREAs)Tz-H and Tz-Cl were designed and synthesized.Replacing thiazole in Tz-H with 4-chlorothiazole can not only remarkably shorten the synthetic route through C—H direct arylation but also enhance molecular planarity with the simultaneous incorporation of S…N and S…Cl noncovalently conformational locks(NoCLs).The photovoltaic devices based on PM6:Tz-Cl exhibited a power conversion efficiency as high as 11.10%,much higher than that of PM6:Tz-H(6.41%),mainly due to more efficient exciton dissociation,better and more balanced carrier mobility,less charge recombination,and more favorable morphology.These findings demonstrate the great potential of NoCLs in achieving low-cost and high-performance NFREAs.
基金supported by the National Natural Science Foundation of China (21871201)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)。
文摘Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the persistent radical anion(PRA)(possessing the properties of both radical and anion) was developed for NIR photocontrolled reversible additionfragmentation chain transfer(RAFT) polymerization,enabling successful polymerization while gaining a deep insight into the mechanism of photo-induced electron transfer RAFT(PET-RAFT) polymerization.Different from the conventional and wellaccepted reductive quenching(RQ) pathway,in which the radical anion intermediates of PCs(PCs^(·-)) must be generated in an excited state(ES),here,the PRA(3,4,9,10-perylenetetracarboxylic dianhydride radical anion(PTCDA^(·-))) could generate conveniently in situ in the ground state(GS) and subsequently serve as highly efficient PC in the NIR region(740–850 nm).The successful implementation of this strategy elucidates the peculiar role played by light and the real way of electron transfer behaviors.In fact,the transfer of a single electron from PRA to chain transfer agent(CTA) and cleavage of the C–S bonds is a process from ES to GS,rather than always from GS(PCs^(·-)) to GS(CTA) in the RQ pathway as is well known to all.In addition,the excellent spatial-temporal control and powerful penetration ability of the NIR light were also confirmed by this PRAcatalyzed polymerization system.
基金The authors acknowledge the generous financial support from the National Natural Science Foundation of China(Nos.52302139,61973103,52272141,and 51972060)Doctoral Foundation Project of Henan University of Technology(No.2021BS069)+3 种基金Natural Science Foundation of Henan Province Youth Fund(No.222300420039)the Key Science and Technology Program of Henan Province(Nos.222102210023 and 232102211074)Project of Songshan Laboratory(No.YYJC072022020)Key Specialized Research of Zhengzhou Science and Technology Innovation Cooperation(No.21ZZXTCX01).
文摘Near-infrared(NIR)phosphor-converted light-emitting diodes/laser diodes(LEDs/LDs)are prospective lighting sources for NIR spectroscopy.However,developing NIR phosphor materials with desired thermal robustness and high photoelectric efficiency is a crucial challenge for their applications.In this work,based on the cationic radius matching effect,a series of(Lu,Y)_(3)(Al,Sc,Cr)_(2)Al_(3)O_(12)NIR phosphor ceramics(LuYScCr NIR-PCs)were fabricated by vacuum sintering.Excellent thermal stability(95%@150℃)was obtained in the prepared NIR-PCs,owing to their weak electron-phonon coupling effect(small Huang-Rhys factor).Being excited at 460 nm,NIR-PCs realized a broadband emission(650-850 nm)with internal quantum efficiency(IQE)of 60.68%.Combining NIR-PCs with LED/LD chips,the maximum output power of the encapsulated LED prototype was 447 mW@300 mA with photoelectric efficiency of as high as 18.6%@180 mA,and the maximum output power of the LD prototype was 814 mW@2.5 A.The working temperatures of NIR-PCs were 70.8℃@300 mA(LED)and 102.8℃@3 A(LD).Finally,the prepared NIR-PCs applied in food detection were verified in this study,demonstrating their anticipated application prospects in the future.