设计和合成结构新颖的聚合物太阳能电池给体材料是有机电子学的热点研究领域.首先利用二噻吩取代的苯并二噻吩(DBDT)作为富电子结构单元,吡咯并吡咯二酮(DPP)作为缺电子单元构筑了一种新的聚合物太阳能电池电子给体材料(PDBDTDPP),然后...设计和合成结构新颖的聚合物太阳能电池给体材料是有机电子学的热点研究领域.首先利用二噻吩取代的苯并二噻吩(DBDT)作为富电子结构单元,吡咯并吡咯二酮(DPP)作为缺电子单元构筑了一种新的聚合物太阳能电池电子给体材料(PDBDTDPP),然后以[6,6]-苯基-C61-丁酸甲酯(PC61BM)作为电子受体,借助密度泛函理论(DFT)方法结合不相干的Marcus-Hush电荷传输模型,系统研究了PC61BM-DBDTDPPn=1,2,3,∞体系的分子结构、电子性质、光吸收性质、电荷转移的内重组能和外重组能、激子结合能、电荷传输积分、给体-受体界面上激子分离和电荷复合速率等性质,并利用线性回归方法分析了聚合物重复单元与其光伏性质的关系.结果表明,该聚合物具有较好的平面结构,低的最高占据分子轨道(HOMO)能级,在紫外-可见区具有宽且强的光学吸收、较大的激子束缚能(1.365 e V),小的激子分离内重组能(0.152 e V)和电荷复合内重组能(0.314 e V).在给体-受体界面上,激子分离速率高达1.073×1014 s-1,而电荷复合速率仅为1.797×108 s-1.相比较而言,激子分离速率比电荷复合速率高约6个数量级,表明在给体-受体界面上,光生激子具有很高的分离效率.总之,研究证明PDBDTDPP是一个非常有前途的聚合物太阳能电池给体材料,值得实验上进一步合成及器件化研究.理论研究不仅有助于更深入理解有机化合物结构与其光学、电子性质之间的关系,还可以为合理设计聚合物太阳能电池给体材料提供有价值的参考.展开更多
以烷基噻并[3,2-b]噻吩修饰的苯并[1,2-b:4,5-b']二噻吩(BDT)为给电单元、苯并噻二唑(BT)/氟代苯并噻二唑(FBT)作缺电单元、烷基噻吩作π桥,合成了两个窄带隙交替共聚物:PTTBDT-DTBT和PTTBDT-DTFBT。对比研究发现:通过在聚合物主链...以烷基噻并[3,2-b]噻吩修饰的苯并[1,2-b:4,5-b']二噻吩(BDT)为给电单元、苯并噻二唑(BT)/氟代苯并噻二唑(FBT)作缺电单元、烷基噻吩作π桥,合成了两个窄带隙交替共聚物:PTTBDT-DTBT和PTTBDT-DTFBT。对比研究发现:通过在聚合物主链结构上引入氟取代基,聚合物的溶解性变差、热稳定性提高、吸收光谱发生蓝移、加深了HOMO能级。基于倒置型光伏器件的初步测试结果显示:PTTBDT-DTFBT相比未氟代PTTBDT-DTBT,开路电压(VOC)从0.76 V增加到0.82 V,填充因子(FF)亦从53.04%增至54.52%,虽然短路电流密度(JSC)从6.62 mA cm^(-2)到6.28 mA cm^(-2)略有下降,最终能量转换效率(PCE)从2.67%提高到2.81%。可见通过在聚合物的骨架引入氟原子是一种改善聚合物太阳能电池性能的有效方案。展开更多
以4,8-二酮苯并[1,2-b∶4,5-b']二噻吩为原料,合成了两种新型的2,2'∶6',2″-三联吡啶修饰的苯并二噻吩电子给-受体结构分子(M1和M2),其结构经~1H NMR,^(13)C NMR,IR和元素分析表征。用UV-Vis,FL,TGA和CV研究了M1和M2的性...以4,8-二酮苯并[1,2-b∶4,5-b']二噻吩为原料,合成了两种新型的2,2'∶6',2″-三联吡啶修饰的苯并二噻吩电子给-受体结构分子(M1和M2),其结构经~1H NMR,^(13)C NMR,IR和元素分析表征。用UV-Vis,FL,TGA和CV研究了M1和M2的性能。结果表明:M1和M2均具有良好的热稳定性,热分解温度(T_5)分别为335℃和430℃。由于电子给-受体结构的存在,M1和M2均表现出明显的分子内电荷转移跃迁(ICT),其最大吸收峰分别为446 nm和468 nm,荧光发射峰分别为517 nm和552 nm;起始还原电位分别为-0.57 e V和-0.62 e V,起始氧化电位分别为0.69 e V和0.87 e V。展开更多
Three acceptor-donor-acceptor （A-D-A） small molecules DCAODTBDT, DRDTBDT and DTBDTBDT using dithieno[2,3-d：2＇,3＇-d＇]benzo[1,2-b：4,5-b＇]dithiophene as the central building block, octyl cyanoacetate, 3-octylrhod...Three acceptor-donor-acceptor （A-D-A） small molecules DCAODTBDT, DRDTBDT and DTBDTBDT using dithieno[2,3-d：2＇,3＇-d＇]benzo[1,2-b：4,5-b＇]dithiophene as the central building block, octyl cyanoacetate, 3-octylrhodanine and thiobarbituric acid as the end groups were designed and synthesized as donor materials in solution-processed photovoltaic cells （OPVs）. The impacts of these different electron withdrawing end groups on the photophysical properties, energy levels, charge carrier mobility, morphologies of blend films, and their photovoltaic properties have been systematically investigated. OPVs device based on DRDTBDT gave the best power conversion efficiency （PCE） of 8.34%, which was significantly higher than that based on DCAODTBDT （4.83%） or DTBDTBDT （3.39%）. These results indicate that rather dedicated and balanced consideration of absorption, energy levels, morphology, mobility, etc. for the design of small-molecule-based OPVs （SM-OPVs） and systematic investigations are highly needed to achieve high performance for SM-OPVs.展开更多
The study of the chiroptical properties of thin-film samples of two chiral benzo[1,2-b:4,5-b’]dithiophene-based oligothiophenes with optoelectronic properties was carried out at Diamond B23 beamline using the synchro...The study of the chiroptical properties of thin-film samples of two chiral benzo[1,2-b:4,5-b’]dithiophene-based oligothiophenes with optoelectronic properties was carried out at Diamond B23 beamline using the synchrotron radiation electronic circular dichroism imaging(SR-ECDi)facility.The experimental results support the hypothesis that the non-reciprocal circularly polarized absorption observed in these materials is due to the combined linear dichroism and linear birefringence contributions.The mapping at 50-μM spatial resolution revealed that several species coexist in the mesoscopic chiral domains likely due to different aggregated phases,which were identified in the films by SR-ECDi but could not be detected with benchtop ECD instruments.展开更多
Short-axis substitution, as an effective way to change the optical and electronic properties of the organic semiconductors for organic photovoltaics(OPVs), is a readily approach to modify non-fullerene acceptors, espe...Short-axis substitution, as an effective way to change the optical and electronic properties of the organic semiconductors for organic photovoltaics(OPVs), is a readily approach to modify non-fullerene acceptors, especially for the linear fused rings system. Here, two new fused-ring electron acceptors(CBT-IC and SBT-IC) were designed and developed by short-axis modification based on the dithienyl[1,2-b:4,5-b′]benzodithiophene(BDCPDT) system. Combined with a medium bandgap polymer donor J71, both of the OPV devices exhibit high power conversion efficiency(PCE) over 11%, and ～70% external quantum efficiencies. To better understand how this kind of substitution affects the BDCPDT based acceptors, a comparative analysis is also made with the the plain acceptor BDT-IC without this modification. We believe this work could disclose the great potential and the versatility of BDCPDT block and also enlighten other ladder-type series for further optimization.展开更多
Titanium dioxide(TiO_(2))has been limited in photocatalysis due to its wide band gap(3.2 eV)and limited absorption in the ultraviolet range.Therefore,organic components have been introduced to hybrid with TiO_(2) for ...Titanium dioxide(TiO_(2))has been limited in photocatalysis due to its wide band gap(3.2 eV)and limited absorption in the ultraviolet range.Therefore,organic components have been introduced to hybrid with TiO_(2) for enhanced photocatalytic efficiency under visible light.Here,we report that benzo[1,2-b:4,5-b']dithiophene polymer was an ideal organic material for the preparation of a hybrid material with TiO_(2).The energy band gap of the resulting hybrid material decreased to 2.9 eV and the photocatalytic hydrogen production performance reached 745.0μmol g^(-1) h^(-1) under visible light irradiation.Meanwhile,the material still maintained the stability of hydrogen production performance after 40 h of photocatalytic cycles.The analysis of the transient current response and electrochemical impedance revealed that the main reasons for the enhanced water splitting of the hybrid materials were the faster separation of electron hole pairs and the lower recombination of photocarrier ions.Our findings suggest that polythiophene is a promising organic material for exploring hybrid materials with enhanced photocatalytic hydrogen production.展开更多
文摘设计和合成结构新颖的聚合物太阳能电池给体材料是有机电子学的热点研究领域.首先利用二噻吩取代的苯并二噻吩(DBDT)作为富电子结构单元,吡咯并吡咯二酮(DPP)作为缺电子单元构筑了一种新的聚合物太阳能电池电子给体材料(PDBDTDPP),然后以[6,6]-苯基-C61-丁酸甲酯(PC61BM)作为电子受体,借助密度泛函理论(DFT)方法结合不相干的Marcus-Hush电荷传输模型,系统研究了PC61BM-DBDTDPPn=1,2,3,∞体系的分子结构、电子性质、光吸收性质、电荷转移的内重组能和外重组能、激子结合能、电荷传输积分、给体-受体界面上激子分离和电荷复合速率等性质,并利用线性回归方法分析了聚合物重复单元与其光伏性质的关系.结果表明,该聚合物具有较好的平面结构,低的最高占据分子轨道(HOMO)能级,在紫外-可见区具有宽且强的光学吸收、较大的激子束缚能(1.365 e V),小的激子分离内重组能(0.152 e V)和电荷复合内重组能(0.314 e V).在给体-受体界面上,激子分离速率高达1.073×1014 s-1,而电荷复合速率仅为1.797×108 s-1.相比较而言,激子分离速率比电荷复合速率高约6个数量级,表明在给体-受体界面上,光生激子具有很高的分离效率.总之,研究证明PDBDTDPP是一个非常有前途的聚合物太阳能电池给体材料,值得实验上进一步合成及器件化研究.理论研究不仅有助于更深入理解有机化合物结构与其光学、电子性质之间的关系,还可以为合理设计聚合物太阳能电池给体材料提供有价值的参考.
文摘以烷基噻并[3,2-b]噻吩修饰的苯并[1,2-b:4,5-b']二噻吩(BDT)为给电单元、苯并噻二唑(BT)/氟代苯并噻二唑(FBT)作缺电单元、烷基噻吩作π桥,合成了两个窄带隙交替共聚物:PTTBDT-DTBT和PTTBDT-DTFBT。对比研究发现:通过在聚合物主链结构上引入氟取代基,聚合物的溶解性变差、热稳定性提高、吸收光谱发生蓝移、加深了HOMO能级。基于倒置型光伏器件的初步测试结果显示:PTTBDT-DTFBT相比未氟代PTTBDT-DTBT,开路电压(VOC)从0.76 V增加到0.82 V,填充因子(FF)亦从53.04%增至54.52%,虽然短路电流密度(JSC)从6.62 mA cm^(-2)到6.28 mA cm^(-2)略有下降,最终能量转换效率(PCE)从2.67%提高到2.81%。可见通过在聚合物的骨架引入氟原子是一种改善聚合物太阳能电池性能的有效方案。
文摘以4,8-二酮苯并[1,2-b∶4,5-b']二噻吩为原料,合成了两种新型的2,2'∶6',2″-三联吡啶修饰的苯并二噻吩电子给-受体结构分子(M1和M2),其结构经~1H NMR,^(13)C NMR,IR和元素分析表征。用UV-Vis,FL,TGA和CV研究了M1和M2的性能。结果表明:M1和M2均具有良好的热稳定性,热分解温度(T_5)分别为335℃和430℃。由于电子给-受体结构的存在,M1和M2均表现出明显的分子内电荷转移跃迁(ICT),其最大吸收峰分别为446 nm和468 nm,荧光发射峰分别为517 nm和552 nm;起始还原电位分别为-0.57 e V和-0.62 e V,起始氧化电位分别为0.69 e V和0.87 e V。
基金supported by the Ministry of Science and Technology(2014CB643502,2016YFA0200200)the Natural Science Foundation of China(21404060,51422304,91433101)
文摘Three acceptor-donor-acceptor （A-D-A） small molecules DCAODTBDT, DRDTBDT and DTBDTBDT using dithieno[2,3-d：2＇,3＇-d＇]benzo[1,2-b：4,5-b＇]dithiophene as the central building block, octyl cyanoacetate, 3-octylrhodanine and thiobarbituric acid as the end groups were designed and synthesized as donor materials in solution-processed photovoltaic cells （OPVs）. The impacts of these different electron withdrawing end groups on the photophysical properties, energy levels, charge carrier mobility, morphologies of blend films, and their photovoltaic properties have been systematically investigated. OPVs device based on DRDTBDT gave the best power conversion efficiency （PCE） of 8.34%, which was significantly higher than that based on DCAODTBDT （4.83%） or DTBDTBDT （3.39%）. These results indicate that rather dedicated and balanced consideration of absorption, energy levels, morphology, mobility, etc. for the design of small-molecule-based OPVs （SM-OPVs） and systematic investigations are highly needed to achieve high performance for SM-OPVs.
文摘The study of the chiroptical properties of thin-film samples of two chiral benzo[1,2-b:4,5-b’]dithiophene-based oligothiophenes with optoelectronic properties was carried out at Diamond B23 beamline using the synchrotron radiation electronic circular dichroism imaging(SR-ECDi)facility.The experimental results support the hypothesis that the non-reciprocal circularly polarized absorption observed in these materials is due to the combined linear dichroism and linear birefringence contributions.The mapping at 50-μM spatial resolution revealed that several species coexist in the mesoscopic chiral domains likely due to different aggregated phases,which were identified in the films by SR-ECDi but could not be detected with benchtop ECD instruments.
基金supported by the National Natural Science Foundation of China (61575136, 21504062, 91633301, 91433117, 21572152)the National Key R&D Program of China (2016YFB0400700)+3 种基金the Collaborative Innovation Center of Suzhou Nano Science and Technology (Nano-CIC)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the “111” Project of the State Administration of Foreign Experts Affairs of Chinathe Yunnan Provincial Research Funds on College-Enterprise Collaboration (2015IB016)
文摘Short-axis substitution, as an effective way to change the optical and electronic properties of the organic semiconductors for organic photovoltaics(OPVs), is a readily approach to modify non-fullerene acceptors, especially for the linear fused rings system. Here, two new fused-ring electron acceptors(CBT-IC and SBT-IC) were designed and developed by short-axis modification based on the dithienyl[1,2-b:4,5-b′]benzodithiophene(BDCPDT) system. Combined with a medium bandgap polymer donor J71, both of the OPV devices exhibit high power conversion efficiency(PCE) over 11%, and ～70% external quantum efficiencies. To better understand how this kind of substitution affects the BDCPDT based acceptors, a comparative analysis is also made with the the plain acceptor BDT-IC without this modification. We believe this work could disclose the great potential and the versatility of BDCPDT block and also enlighten other ladder-type series for further optimization.
基金financial support from Hainan Province Natural Science Foundation of China (No. 219QN151)the National Natural Science Foundation of China (21801052)+1 种基金Hainan University Start-up Fund (No. KYQD(ZR)1852)the Construction Program of Research Platform in Hainan University (No. ZY2019HN09)。
文摘Titanium dioxide(TiO_(2))has been limited in photocatalysis due to its wide band gap(3.2 eV)and limited absorption in the ultraviolet range.Therefore,organic components have been introduced to hybrid with TiO_(2) for enhanced photocatalytic efficiency under visible light.Here,we report that benzo[1,2-b:4,5-b']dithiophene polymer was an ideal organic material for the preparation of a hybrid material with TiO_(2).The energy band gap of the resulting hybrid material decreased to 2.9 eV and the photocatalytic hydrogen production performance reached 745.0μmol g^(-1) h^(-1) under visible light irradiation.Meanwhile,the material still maintained the stability of hydrogen production performance after 40 h of photocatalytic cycles.The analysis of the transient current response and electrochemical impedance revealed that the main reasons for the enhanced water splitting of the hybrid materials were the faster separation of electron hole pairs and the lower recombination of photocarrier ions.Our findings suggest that polythiophene is a promising organic material for exploring hybrid materials with enhanced photocatalytic hydrogen production.
