Three small bandgap non-fullerene(SBG NFAs) acceptors,BDTI,BDTI-2 F and BDTI-4 F,based on a carbon-oxygen bridged central core and thieno[3,4-b]thiophene linker,end-capped with varied electronwithdrawing terminal grou...Three small bandgap non-fullerene(SBG NFAs) acceptors,BDTI,BDTI-2 F and BDTI-4 F,based on a carbon-oxygen bridged central core and thieno[3,4-b]thiophene linker,end-capped with varied electronwithdrawing terminal groups,were designed and synthesized.The acceptors exhibit strong absorption from 600 nm to 1000 nm.The optimal device incorporating designed NFA and PTB7-Th polymer donor achieves a power conversion efficiency of 9.11% with near 0 eV HOMO offset.The work presents a case study of efficient non-fullerene solar cells with small HOMO offsets,which is achieved by blending PTB7-Th with fine-tuned SBG acceptor.展开更多
Two simple molecular acceptors, NIDBT and NIDT, bearing the same end groups of 2-（3-oxo-2,3-dihydro-1H-inden-1-ylidene）malononitrile （INCN） yet with different core units, indenofluorenodithiophene （IDBT） and ind...Two simple molecular acceptors, NIDBT and NIDT, bearing the same end groups of 2-（3-oxo-2,3-dihydro-1H-inden-1-ylidene）malononitrile （INCN） yet with different core units, indenofluorenodithiophene （IDBT） and indaceno[2,1-b：6,5-b＇]dithiophene （IDT）, respectively, were adopted to fabri- cate polymer solar cells by blending with a narrow bandgap polymer donor, PBDBTBTT-Hex （P3）. The incorporation of benzene rings into the molecular skeletons generates a negative effect on the photovoltaic performance of resultant molecular acceptor, rendering an inferior power conversion efficiency of 2.45%, compared to 4.05% for the NlDT-based bulk-heterojunction solar cells. Detailed comparison on photovoltaic parameters indicates that the fusion by incorporating two separated benzene rings into the IDT core renders molecular acceptor of weakened intermolecular interaction with the pol- ymer donor, which results in over-aggregated phase separation, unbalanced charge transport, and serious recombination within the photovoltaic devices. The work contributes to a deep understanding of the effect of skeleton-fusion strategy for designing high-performance molecular acceptors.展开更多
With the rapid development in recent years, small-molecule organic solar cell is challenging the dominance of its counterpart, polymer solar cell. The top power conversion efficiencies of both single and tandem solar ...With the rapid development in recent years, small-molecule organic solar cell is challenging the dominance of its counterpart, polymer solar cell. The top power conversion efficiencies of both single and tandem solar cells based on small molecules have surpassed 9%. In this mini review, achievements of small molecules with impressive photovoltaic performance especially reported in the last two years were highlighted. The relationship between molecular structure and device performance was analyzed, which draws some rules for rational molecular design. Five series of p- and n-type small molecules were selected based on the consideration of their competitiveness of power conversion efficiencies.展开更多
基金the National Key R&D Program of China (2017YFA0204701)Strategic Priority Research Program of the Chinese Academy of Sciences (XDB12010200)+1 种基金National Basic Research Program of China (Program 973) (No. 2014CB643502)the National Natural Science Foundation of China (21572234, 21661132006, 91833304, 21402194) for their financial support。
文摘Three small bandgap non-fullerene(SBG NFAs) acceptors,BDTI,BDTI-2 F and BDTI-4 F,based on a carbon-oxygen bridged central core and thieno[3,4-b]thiophene linker,end-capped with varied electronwithdrawing terminal groups,were designed and synthesized.The acceptors exhibit strong absorption from 600 nm to 1000 nm.The optimal device incorporating designed NFA and PTB7-Th polymer donor achieves a power conversion efficiency of 9.11% with near 0 eV HOMO offset.The work presents a case study of efficient non-fullerene solar cells with small HOMO offsets,which is achieved by blending PTB7-Th with fine-tuned SBG acceptor.
基金The authors gratefully acknowledge the financial support from National Basic Research Program of China [973 Program, No. 2014CB643502）, the Strategic Priority Research Program of the Chinese Academy of Sciences （No. XDB12010200）, the National Natural Science Foundation of China （Nos. 91333113, 21572234, 61505225）.
文摘Two simple molecular acceptors, NIDBT and NIDT, bearing the same end groups of 2-（3-oxo-2,3-dihydro-1H-inden-1-ylidene）malononitrile （INCN） yet with different core units, indenofluorenodithiophene （IDBT） and indaceno[2,1-b：6,5-b＇]dithiophene （IDT）, respectively, were adopted to fabri- cate polymer solar cells by blending with a narrow bandgap polymer donor, PBDBTBTT-Hex （P3）. The incorporation of benzene rings into the molecular skeletons generates a negative effect on the photovoltaic performance of resultant molecular acceptor, rendering an inferior power conversion efficiency of 2.45%, compared to 4.05% for the NlDT-based bulk-heterojunction solar cells. Detailed comparison on photovoltaic parameters indicates that the fusion by incorporating two separated benzene rings into the IDT core renders molecular acceptor of weakened intermolecular interaction with the pol- ymer donor, which results in over-aggregated phase separation, unbalanced charge transport, and serious recombination within the photovoltaic devices. The work contributes to a deep understanding of the effect of skeleton-fusion strategy for designing high-performance molecular acceptors.
基金supported by the National Basic Research Program of China(2014CB643502)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB12010200)the National Natural Science Foundation of China(91333113)
文摘With the rapid development in recent years, small-molecule organic solar cell is challenging the dominance of its counterpart, polymer solar cell. The top power conversion efficiencies of both single and tandem solar cells based on small molecules have surpassed 9%. In this mini review, achievements of small molecules with impressive photovoltaic performance especially reported in the last two years were highlighted. The relationship between molecular structure and device performance was analyzed, which draws some rules for rational molecular design. Five series of p- and n-type small molecules were selected based on the consideration of their competitiveness of power conversion efficiencies.
