基于定压供气的压缩空气储能系统研究

为解决压缩空气储能电站中储气装置容积庞大、制约系统经济性的问题,采用定压供气方案,使储气装置的容积缩减至常规方案的49.63%,从而降低投资成本。通过使用Aspen Plus V11软件模拟计算后,系统的电—电转换效率达到62.48%。综合分析结果表明,该系统具有广泛的应用前景,可为清洁能源应用和能源转型提供经济可行的解决方案。

Selective synthesis of Sb2S3 nanostructures with different morphologies for high performance in dye-sensitized solar cells

In this work,we initially synthesized Sb2S3 with uniform flower-like structures via a facile hydrothermal method through the modification of the Sb source and pH value.Afterward,Sb2S3 with a nanosheet structure was successfully synthesized on reduced graphene oxide(Sb2S3@RGO).The flower-like Sb2S3 and the Sb2S3@RGO nanosheets were tested as the counter electrode(CE)of dye-sensitized solar cells,and the latter exhibited a higher electrocatalytic property than the former owing to the introduction of graphene.The results from electrochemical tests indicated that the as-prepared Sb2S3@RGO nanosheets possess higher catalytic activity,charge-transfer ability,and electrochemical stability than Sb2S3,RGO,and Pt CEs.More notably,the power conversion efficiency of Sb2S3@RGO reached 8.17%,which was higher than that of the standard Pt CE(7.75%).

Alloy-like ternary polymer solar cells with over 17.2% efficiency

Ternary strategy has been considered as an efficient method to achieve high performance polymer solar cells(PSCs). A power conversion efficiency(PCE) of 17.22% is achieved in the optimized ternary PSCs with10 wt% MF1 in acceptors. The over 8% PCE improvement by employing ternary strategy is attributed to the simultaneously increased JSCof 25.68 mA cm^-2, VOCof 0.853 V and FF of 78.61% compared with Y6 based binary PSCs. The good compatibility of MF1 and Y6 can be confirmed from Raman mapping, contact angle,cyclic voltammetry and morphology, which is the prerequisite to form alloy-like state. Electron mobility in ternary active layers strongly depends on MF1 content in acceptors due to the different lowest unoccupied molecular orbital(LUMO) levels of Y6 and MF1, which can well explain the wave-like varied FF of ternary PSCs. The third-party certified PCE of 16.8% should be one of the highest values for single bulk heterojunction PSCs. This work provides sufficient references for selecting materials to achieve efficient ternary PSCs.

CsPbBrI perovskites with low energy loss for high-performance indoor and outdoor photovoltaics

Over the years,the efficiency of inorganic perovskite solar cells(PSCs)has increased at an unprecedented pace.However,energy loss in the device has limited a further increase in efficiency and commercialization.In this work,we used(NH4)2C2O4·H2O to treat CsPbBrI2 perovskite film during spin-coating.The CsPbBrI2 underwent secondary crystallization to form high quality films with micrometer-scale and low trap density.(NH4)2C2O4·H2O treatment promoted charge transfer capacity and reduced the ideal factor.It also dropped the energy loss from 0.80 to 0.64 eV.The resulting device delivered a power conversion efficiency(PCE)of 16.55%with an open-circuit voltage(Voc)of 1.24 V,which are largely improved compared with the reference device which exhibited a PCE of 13.27%and a Voc of 1.10 V.In addition,the optimized treated device presented a record indoor PCE of 28.48%under a fluorescent lamp of 1000 lux,better than that of the reference device(19.05%).

A low-temperature TiO2/SnO2 electron transport layer for high-performance planar perovskite solar cells

Conventional titanium oxide(TiO2) as an electron transport layer(ETL) in hybrid organic-inorganic perovskite solar cells(PSCs) requires a sintering process at a high temperature to crystalize, which is not suitable for flexible PSCs and tandem solar cells with their low-temperatureprocessed bottom cell. Here, we introduce a low-temperature solution method to deposit a TiO2/tin oxide(SnO2) bilayer towards an efficient ETL. From the systematic measurements of optical and electronic properties, we demonstrate that the TiO2/SnO2 ETL has an enhanced charge extraction ability and a suppressed carrier recombination at the ETL/perovskite interface, both of which are beneficial to photo-generated carrier separation and transport. As a result, PSCs with TiO2/SnO2 bilayer ETLs present higher photovoltaic performance of the baseline cells compared with their TiO2 and SnO2 single-layer ETL counterparts. The champion PSC has a power conversion efficiency(PCE) of 19.11% with an open-circuit voltage(Voc)of 1.15 V, a short-circuit current density(Jsc) of 22.77 mA cm^-2,and a fill factor(FF) of 72.38%. Additionally, due to the suitable band alignment of the TiO2/SnO2 ETL in the device, a high Vocof 1.18 V is achieved. It has been proven that the TiO2/SnO2 bilayer is a promising alternative ETL for high efficiency PSCs.

Interfacial stabilization for inverted perovskite solar cells with long-term stability

Perovskite solar cells(PSCs)commonly exhibit significant performance degradation due to ion migration through the top charge transport layer and ultimately metal electrode corrosion.Here,we demonstrate an interfacial management strategy using a boron chloride subphthalocyanine(Cl_(6)SubPc)/fullerene electron-transport layer,which not only passivates the interfacial defects in the perovskite,but also suppresses halide diffusion as evidenced by multiple techniques,including visual element mapping by electron energy loss spectroscopy.As a result,we obtain inverted PSCs with an efficiency of 22.0%(21.3%certified),shelf life of 7000 h,T_(80) of 816 h under damp heat stress(compared to less than 20 h without Cl_(6)SubPc),and initial performance retention of 98%after 2000 h at 80℃in inert environment,90%after 2034 h of illumination and maximum power point tracking in ambient for encapsulated devices and 95%after 1272 h outdoor testing ISOS-O-1.Our strategy and results pave a new way to move PSCs forward to their potential commercialization solidly.

Manipulate energy transport via fluorinated spacers towards recordefficiency 2D Dion-Jacobson CsPbI_(3) solar cells

Two-dimensional(2D)Dion-Jacobson(D-J)-type cesium lead iodide CsPbI_(3) perform remarkably in terms of stability.However,the complex interactions between spacer and inorganic layers limit its excellent progress in perovskite solar cells(PSCs).Herein,starting from the considerable structural diversity of organic spacers,we engineer 2D CsPbI_(3) with fine-tuning functionalities.Specifically,for the first time we embedded fluorinated aromatic cations in 2D D-J CsPbI_(3),and successfully applied it into construction of high-performance PSCs.Compared with constitutive 1,4-diaminobenzene(PDA),the fluorinated 2-fluorobenzene-1,4-diamine(F-PDA)component greatly expands the dipole moment from 0.59 D to 3.47 D,which reduces the exciton binding energy of the system.A theoretical study shows that the spacer layer and inorganic plane are more enriched with charge accumulation in(F-PDA)Csn±1 Pb_(n)I_(3n+1).The results show that(F-PDA)Csn±1Pb_(n)I_(3n+1) demonstrates more significant charge transfer between organic and inorganic layers than(PDA)Csn±1 Pb_(n)I_(3n+1),and it is confirmed in the femtosecond transient absorption experiment.Moreover,the interactions of the fluorinated spacer with the[PbI_(6)]_(4)-plane effectively manipulate the crystallization quality,and thus the ion migration and defect formation of target 2D CsPbI_(3) are inhibited.As a result,we obtained a record power conversion efficiency(PCE)beyond 15%for 2D D-J(F-PDA)Cs_(3)Pb_(4)I_(13)(n=4)PSCs with significantly improved environmental stability compared with the three-dimensional(3D)counterparts.

Grain boundary passivation with triazine-graphdiyne to improve perovskite solar cell performance

Detrimental defects on perovskite grain boundaries(GBs)are critical factors that lead to non-radiative recombination and hysteresis.In this work,triazine-graphdiyne(Tra-GD),a nitrogen-rich two-dimensional(2 D)material,was incorporated into the active layer of perovskite to modify the GBs.Tra-GD was found to distribute evenly over the bulk of the perovskite and has a strong interaction with the Pb^2+ exposed at GBs,which enables it to effectively passivate GB defects and prevent ion migration.The results of Kelvin probe force microscopy and photoluminescence studies proved that the highly conjugated Tra-GD located at GBs could promote charge extraction and transport.Benefiting from defect passivation and more efficient carrier transport,the Tra-GD based device showed less non-radiative recombination loss.Consequently,the resultant device presented negligible hysteresis and yielded a high power conversion efficiency(PCE)of 20.33%in the MAPbI3-based perovskite solar cell.This approach was extended to the FAPbI3 system with a PCE of 21.16%.Our Tra-GD passivation strategy provides a useful approach to effectively improving the device performance and addressing hysteresis issues.

Stable tin perovskite solar cells enabled by widening the time window for crystallization

Tin perovskite solar cells (TPSCs) are the most promising candidates for lead-free perovskite solar cells(PSCs).However,the poor crystallization and chemical stability of Sn perovskites are the two challenging issues for further application of TPSCs.Here,we present a strategy to stabilize CH(NH_(2))2SnI3(FASnI3) perovskite enabled by an amine complex,CH3NH3I·3CH3NH_(2),which can hinder the major degradation issue caused by the oxidation of Sn2+to Sn4+.The resulting Sn perovskite films exhibit enhanced crystallinity and stability in comparison with those made with conventional inorganic SnF2 additives.Finally,the device achieved a higher external quantum efficiency for charge extraction and a power conversion efficiency (PCE) of 9.53%,which maintained more than 90%of the initial efficiency after1000 h of light soaking under the standard AM 1.5 G solar illumination.

Tailoring organic bulk-heterojunction for charge extraction and spectral absorption in CsPbBr perovskite solar cells

All-inorganic CsPbBr_(3)perovskite solar cells(PSCs)are promising candidates to balance the stability and efficiency issues of organic-inorganic hybrid devices.However,the large energy barrier for charge transfer and narrow spectral response are still two challenging problems for performance improvement.We present here an organic bulkheterojunction{poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61 butyric acid methyl ester(P3HT:PCBM)}photoactive layer to boost the charge extraction and to widen the spectral absorption,achieving an enhanced power conversion efficiency up to 8.94%by optimizing the thickness of P3HT:PCBM photoactive layer,which is much higher than 6.28%for the pristine CsPbBr_(3)device.The interaction between the carbonyl group in PCBM and unsaturated Pb atom in the perovskite surface can effectively passivate the defects and reduce charge recombination.Furthermore,the coupling effect between PCBM and P3HT widens the spectral response from 540 to 650 nm for an increased short-circuit current density.More importantly,the devices are relatively stable over 75 days upon persistent attack by 70%relative humidity in air condition.These advantages of high efficiency,excellent long-term stability,cost-effectiveness and scalability may promote the commercialization of inorganic PSCs.

Inverted polymer solar cells with a solution-processed zinc oxide thin film as an electron collection layer

A solution-processed zinc oxide (ZnO) thin film as an electron collection layer for polymer solar cells (PSCs) with an inverted device structure was investigated. Power conversion efficiencies (PCEs) of PSCs made with a blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) are 3.50% and 1.21% for PSCs with and without the ZnO thin film, respectively. Light intensity dependence of the photocurrent and the capacitance-voltage measurement demonstrate that the increased PCEs are due to the restriction of the strong bimolecular recombination in the interface when a thin ZnO layer is inserted between the polymer active layer and the ITO electrode. These results demonstrate that the ZnO thin film plays an important role in the performance of PSCs with an inverted device structure.

Theoretical insight into the stereometric effect of bisPC71BM on polymer cell performance

It has been experimentally demonstrated that the stereometric packings of two new bisPC_(71) BM isomers have an important impact on the power conversion efficiency of organic solar cells. Here, a theoretical investigation is made to reveal the mechanism behind from detailed photophysical processes in performed cells. The results show that the crystal packings of isomers affect the electron mobilities dominantly from the electronic coupling for electron transfer, and the trends of calculated mobilities are consistent with experimental measurements although the magnitudes are obviously larger. For the performed cells from two isomers with poly(3-hexylthiophene) as a donor, it is found that the exciton dissociation yields are also different, manifesting that stereometric packings essentially control the cell efficiency via both electron mobilities and exciton dissociation. Furthermore,the reasons for low cell efficiencies are analyzed, and possible improvements are suggested.

Formation of efficient dye-sensitized solar cells by introducing an interfacial layer of hierarchically ordered macro-mesoporous TiO_2 film

Hierarchically ordered macro-mesoporous TiO2 films (Ti-Ma-Me) were fabricated on fluorine-doped tin oxide (FTO) substrates through the confinement self-assembly method. The prepared Ti-Ma-Me possesses periodically ordered structure and a large specific surface area, which was applied as an interfacial layer between the nanocrystalline TiO2 film (P25-TiO2) and FTO electrode in the dye-sensitized solar cell (DSSC). The introduction of a Ti-Ma-Me interfacial layer increased the shortcircuit current density (Jsc) from 7.49 to 10.65 mA/cm2 and the open-circuit voltage (Voc) from 0.65 to 0.70 V as the result of its improved light harvesting efficiency by allowing for the high roughness factor and enhanced multiple internal reflection or scattering as well as reducing the back-transport reaction by blocking direct contact between the electrolyte and FTO electrode. Therefore, the photovoltaic conversion efficiency (η) was improved by 83% from 3.04% to 5.55%, as compared to a device using a bare P25 TiO2 photoanode.

Boosting optoelectronic performance of MAPbI3 perovskite solar cells via ethylammonium chloride additive engineering

The quality of the perovskite light absorption layer plays a dynamic role in the photovoltaic properties of solar cells.The existing methods to prepare methylammonium lead iodide(MAPbI3)films render substantial structural defect density,particularly at the grain boundaries and film surface,constituting a challenge that hinders the further optoelectronic enhancement of perovskite solar cells.Herein,a unique approach was introduced:using a simple ethylammonium chloride(EACl)additive in perovskite precursor mixture to produce high-quality MAPbI3 thin films.The results indicated that EACl could encourage perovskite crystal growth without experiencing the intermediate phase formation and would evaporate from the perovskite after annealing.Additionally,a gradient perovskite structure was achieved using this technique,which impressively enhanced the performance of the perovskite films.A high power conversion efficiency(PCE)of 20.03%was achieved under the optimal amount of EACl,and the resultant efficient device could retain over 89%of the original PCE after aging for 1000 h at room temperature.This novel technique leads to a facile fabrication of highquality and less-defect perovskite thin films for competent and stable devices.

Graphdiyne oxide-accelerated charge carrier transfer and separation at the interface for efficient binary organic solar cells

Interfacial engineering for the regulation of the charge carrier dynamics in solar cells is a critical factor in the fabrication of high-efficiency devices.Based on the successful preparation of highly dispersible graphdiyne oxide(GDYO)with a large number of functional groups,we fabricated organic solar cells employing GDYO-modified poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate)(PEDOT:PSS)as hole transport materials.Results show that theπ±πinteraction between GDYO and PEDOT:PSS is beneficial to the formation of an optimized charge carrier transfer channel and improves the conductivity and charge carrier mobility in the hole transport layer.Moreover,the improved interfacial contact contributes to the suppression of charge carrier recombination and the elevation of charge carrier extraction between the hole transport layer and the active layer.More importantly,the occurrence of charge carrier separation benefits from the optimized morphology of the active layer,which efficiently improves the performance,as proven by the results of transient absorption measurements.Therefore,with the holistic management approach to the multiobjective optimization of the charge carrier dynamics,a photoelectric conversion efficiency of 17.5%(with the certified value of 17.2%)is obtained for binary organic solar cells.All of these results indicate the potential application of the functionalized graphdiyne in the field of organic optoelectronic devices.

Improving UV stability of perovskite solar cells without sacrificing efficiency through light trapping regulated spectral modification

The stability of perovskite solar cells is an important issue to be addressed for future applications.Perovskite solar cells are vulnerable to exposure to UV light due to promoted chemical reactions.However, preventing UV light from entering solar cells lowers the power conversion efficiency by reducing the photocurrent. The challenge is to improve UV stability without sacrificing efficiency. Here, we demonstrate the reduction of UV light-related negative effects from the perspective of spectral modification. By simultaneously introducing UV–visible downshifting and light trapping, perovskite solar cells can achieve a comparable efficiency of over 21% to that of an unmodified device. The optimized device obtains increased UV stability due to UV–visible downshifting. Different from other strategies, spectral modification externally alters the composition of incident light and improves UV stability without changing the internal device architecture, which is broadly applicable to perovskite solar cells with different structures. The present work may also find applications in other types of solar cells to boost the stability of devices exposed to UV light.

Furan-based liquid-crystalline small-molecule donor guest improving the photovoltaic performance of organic solar cells with amorphous packing

Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve the performance of organic solar cells(OSCs).Contrary to conventional understanding,this research proposes a new strategy for ternary OSCs implicating that"weakly crystalline materials can also optimize the morphology of the active layer and improve the OSCs performance".Herein,we designed and synthesized two liquid-crystalline SMDs,Z1 and Z2,based on benzodifuran(BDF)units.The amorphous Z2-incorporated ternary devices present an unexpectedly improved power conversion efficiency(PCE)>18%with good stability.By contrast,the highly ordered Z1-based ternary devices possess a significantly depressed efficiency.Multiple characterizations reveal that the Z2-based ternary blend films possess improved miscibility and efficient charge transport.This novel strategy for the selection of the third component is significant for the fabrication of high-efficiency ternary OSCs.

Fullerenes and derivatives as electron transport materials in perovskite solar cells

In this study,two fullerenes(C60,C70)and their methano-substitutions(PC61BM,PC71BM),as electron transport materials(ETMs)in perovskite solar cells(Pero-SCs),were systematically studied.As being used as ETMs,methanofullerenes,though with lower electron mobility compared to the counterpart pristine fullerenes,lead to higher power conversion efficiencies(PCEs)of Pero-SCs.The difference is likely caused by the fill-out vacancies and smoother morphology of the interfaces between ETM and perovskite layers,as they were prepared by different methods.In addition,compared to C60 and PC61BM,C70 and PC71BM showed priority in terms of short-circuit current density,which should be attributed to fast free charge extraction abilities.

Comprehensive study of efficient dye-sensitized solar cells based on the binary ionic liquid electrolyte by modifying with additives and iodine

The photovoltaic performance of dye-sensitized solar cells （DSSCs） is enhanced by modifying the binary room tem- perature ionic liquid （RTIL） electrolyte with additives and iodine. The average photoelectric conversion efficiency （PCE） of 6.39% is achieved. Through electrochemical impedance spectroscopy （EIS）, cyclic voltammetry scans and incident photon-to-current conversion efficiency （1PCE） data, the working principles are analyzed. The enhancement is mainly attributed to the improvement of short circuit current which is caused by the reduction of overall internal resistance of the devices. Durability tests are measured at room temperature, and the long-term stability performance can be maintained.

Coordination engineering of Cu-Zn-Sn-S aqueous precursor for efficient kesterite solar cells

Aqueous precursors provide an alluring approach for low-cost and environmentally friendly production of earth-abundant Cu2ZnSn(S,Se)4(CZTSSe)solar cells.The key is to find an appropriate molecular agent to prepare a stable solution and optimize the coordination structure to facilitate the subsequent crystallization process.Herein,we introduce thioglycolic acid(TGA),which possesses strong coordination(SH)and hydrophilic(COOH)groups,as the agent and use deprotonation to regulate the coordination competition within the aqueous solution.Ultimately,metal cations are adequately coordinated with thiolate anions,and carboxylate anions are released to become hydrated to form an ultrastable aqueous solution.These factors have contributed to achieving CZTSSe solar cells with an efficiency as high as 12.3%(a certified efficiency of 12.0%)and providing an extremely wide time window for precursor storage and usage.This work represents significant progress in the non-toxic solution fabrication of CZTSSe solar cells and holds great potential for the development of CZTSSe and other metal sulfide solar cells.