Bulk heterojunction,non-fullerene PBDB-T:ITIC blend polymer solar cells have been fabricated.The active layers consisting of PBDB-T as a donor and ITIC as an acceptor are optimized using a series of alkylthiol additiv...Bulk heterojunction,non-fullerene PBDB-T:ITIC blend polymer solar cells have been fabricated.The active layers consisting of PBDB-T as a donor and ITIC as an acceptor are optimized using a series of alkylthiol additives(1,3-propanedithiol,1,4-butanedithiol,and 1,8-octanedithiol).It is found that the donor and acceptor are phase separated with different crystalline domains.The additives effectively re-organize the morphology and extend the molecule ordering in lamellar structure with increased correlation length in ITIC domain,benefiting the generation and dissociation of exciton and reducing charge recombination.A substantial improvement in power conversion efficiency of the devices from 8.13%to 9.44%is observed.This study shows that the application of alkylthiol additives is a simple and effective approach to improve the device performance in solar cells based on polymer/non-fullerene blend system.展开更多
Bulk heterojunction(BHJ) solar cells based on small molecules have attracted potential attention due to their promise of conveniently defined structures, high absorption coefficients, solution process-ability and easy...Bulk heterojunction(BHJ) solar cells based on small molecules have attracted potential attention due to their promise of conveniently defined structures, high absorption coefficients, solution process-ability and easy fabrication. Three D—A—D—A type organic semiconductors(WS-31,WS-32 and WS-52) are synthesized, based on the indoline donor and benzotriazole auxiliary acceptor core, along with either bare thiophene or rigid cyclopentadithiophene as π bridge, rhodanine or carbonocyanidate as end-group. Their HOMO orbitals are delocalized throughout the whole molecules. Whereas the LUMOs are mainly localized on the acceptor part of structure, which reach up to benzothiadiazole, but no distribution on indoline donor. The first excitations for WS-31 and WS-32 are mainly originated by electron transition from HOMO to LUMO level, while for WS-52, partly related to transition between HOMO and LUMO+1 level. The small organic molecules are applied as donor components in bulk heterojunction(BHJ) organic solar cells, using PC_(61)BM as acceptor material to check their photovoltaic performances. The BHJ solar cells based on blended layer of WS-31:PC_(61)BM and WS-32:PC_(61)BM processed with chloroform show overall photoelectric conversion efficiency(PCE) of 0.56% and 1.02%, respectively. WS-32 based BHJ solar cells show a higher current density originated by its relatively larger driving force of photo-induced carrier in photo-active layer to LUMO of PC_(61)BM.展开更多
Control of blend morphology at multi-scale is critical for optimizing the power conversion efficiency(PCE)of plastic solar cells.To better understand the physics of photoactive layer in the organic photovoltaic device...Control of blend morphology at multi-scale is critical for optimizing the power conversion efficiency(PCE)of plastic solar cells.To better understand the physics of photoactive layer in the organic photovoltaic devices,it is necessary to gain understanding of morphology and the corresponding electronic property.Herein we report the correlation between nanoscale structural,electric properties of bulk heterojunction(BHJ)solar cells and the annealing-induced PCE change.We demonstrate that the PCE of BHJ solar cells are dramatically improved(from1.3%to 4.6%)by thermal annealing,which results from P3HT crystalline stacking and the PCBM aggregation for interpenetrated network.The similar trend for annealinginduced photovoltage and PCE evolution present as an initial increase followed by a decrease with the annealing time and temperature.The surface roughness increase slowly and then abruptly after the same inflection points observed for photovoltage and PCE.The phase images in electric force microscopy indicate the optimized P3HT and PCBM crystallization for interpenetrating network formation considering the spectroscopic results as well.From the correlation between surface photovoltage,blend morphology,and PCE,we propose a model to illustrate the film structure and its evolution under different annealing conditions.This work would benefit the better design and optimization of the morphology and local electric properties of solar cell active layers for improved PCE.展开更多
The development of organic solar cells(OSCs) has focused on optimizing donor and acceptor materials and their morphology in bulk heterojunctions(BHJs), leading to efficiencies over 20% [1-6].
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474017,61574014, and 61874008)
文摘Bulk heterojunction,non-fullerene PBDB-T:ITIC blend polymer solar cells have been fabricated.The active layers consisting of PBDB-T as a donor and ITIC as an acceptor are optimized using a series of alkylthiol additives(1,3-propanedithiol,1,4-butanedithiol,and 1,8-octanedithiol).It is found that the donor and acceptor are phase separated with different crystalline domains.The additives effectively re-organize the morphology and extend the molecule ordering in lamellar structure with increased correlation length in ITIC domain,benefiting the generation and dissociation of exciton and reducing charge recombination.A substantial improvement in power conversion efficiency of the devices from 8.13%to 9.44%is observed.This study shows that the application of alkylthiol additives is a simple and effective approach to improve the device performance in solar cells based on polymer/non-fullerene blend system.
基金supported by the NSFC for Creative Research Groups(21421004)Distinguished Young Scholars(21325625)+4 种基金NSFC/China,Science and Technology Commission of Shanghai Municipality(14YF1410500 and 15XD1501400)Shanghai Young Teacher Supporting Foundation(ZZEGD14011)Program for Professor of Special Appointment(Eastern Scholar)"Shu Guang" project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation(13SG55)Grants of computing timeat the C3SE supercomputing Center at Chalmers(Gteborg)
文摘Bulk heterojunction(BHJ) solar cells based on small molecules have attracted potential attention due to their promise of conveniently defined structures, high absorption coefficients, solution process-ability and easy fabrication. Three D—A—D—A type organic semiconductors(WS-31,WS-32 and WS-52) are synthesized, based on the indoline donor and benzotriazole auxiliary acceptor core, along with either bare thiophene or rigid cyclopentadithiophene as π bridge, rhodanine or carbonocyanidate as end-group. Their HOMO orbitals are delocalized throughout the whole molecules. Whereas the LUMOs are mainly localized on the acceptor part of structure, which reach up to benzothiadiazole, but no distribution on indoline donor. The first excitations for WS-31 and WS-32 are mainly originated by electron transition from HOMO to LUMO level, while for WS-52, partly related to transition between HOMO and LUMO+1 level. The small organic molecules are applied as donor components in bulk heterojunction(BHJ) organic solar cells, using PC_(61)BM as acceptor material to check their photovoltaic performances. The BHJ solar cells based on blended layer of WS-31:PC_(61)BM and WS-32:PC_(61)BM processed with chloroform show overall photoelectric conversion efficiency(PCE) of 0.56% and 1.02%, respectively. WS-32 based BHJ solar cells show a higher current density originated by its relatively larger driving force of photo-induced carrier in photo-active layer to LUMO of PC_(61)BM.
基金supported by the National Basic Research Program of China(2011CB932800 and 2013CB934200)Sino-British Collaboration Program(2010DFA64680)+1 种基金National Natural Science Foundation of China(20973043)Chinese Academy of Sciences(KGCX2-YW-375-3)
文摘Control of blend morphology at multi-scale is critical for optimizing the power conversion efficiency(PCE)of plastic solar cells.To better understand the physics of photoactive layer in the organic photovoltaic devices,it is necessary to gain understanding of morphology and the corresponding electronic property.Herein we report the correlation between nanoscale structural,electric properties of bulk heterojunction(BHJ)solar cells and the annealing-induced PCE change.We demonstrate that the PCE of BHJ solar cells are dramatically improved(from1.3%to 4.6%)by thermal annealing,which results from P3HT crystalline stacking and the PCBM aggregation for interpenetrated network.The similar trend for annealinginduced photovoltage and PCE evolution present as an initial increase followed by a decrease with the annealing time and temperature.The surface roughness increase slowly and then abruptly after the same inflection points observed for photovoltage and PCE.The phase images in electric force microscopy indicate the optimized P3HT and PCBM crystallization for interpenetrating network formation considering the spectroscopic results as well.From the correlation between surface photovoltage,blend morphology,and PCE,we propose a model to illustrate the film structure and its evolution under different annealing conditions.This work would benefit the better design and optimization of the morphology and local electric properties of solar cell active layers for improved PCE.
文摘The development of organic solar cells(OSCs) has focused on optimizing donor and acceptor materials and their morphology in bulk heterojunctions(BHJs), leading to efficiencies over 20% [1-6].
