The non-fully conjugated polymer as a new class of acceptor materials has shown some advantages over its small molecular counterpart when used in photoactive layers for all-polymer solar cells(all-PSCs),despite a low ...The non-fully conjugated polymer as a new class of acceptor materials has shown some advantages over its small molecular counterpart when used in photoactive layers for all-polymer solar cells(all-PSCs),despite a low power conversion efficiency(PCE)caused by its narrow absorption spectra.Herein,a novel non-fully conjugated polymer acceptor PFY-2TS with a low bandgap of~1.40 eV was developed,via polymerizing a largeπ-fused small molecule acceptor(SMA)building block(namely YBO)with a non-conjugated thioalkyl linkage.Compared with its precursor YBO,PFY-2TS retains a similar low bandgap but a higher LUMO level.Moreover,compared with the structural analog of YBO-based fully conjugated polymer acceptor PFY-DTC,PFY-2TS shows a similar absorption spectrum and electron mobility,but significantly different molecular crystallinity and aggregation properties,which results in optimal blend morphology with a polymer donor PBDB-T and physical processes of the device in all-PSCs.As a result,PFY-2TS-based all-PSCs achieved a PCE of 12.31%with a small energy loss of 0.56 eV enabled by the reduced non-radiative energy loss(0.24 eV),which is better than that of 11.08%for the PFY-DTC-based ones.Our work clearly demonstrated that non-fully conjugated polymers as a new class of acceptor materials are very promising for the development of high-performance all-PSCs.展开更多
A high performance polymer solar cells(PSCs) based on polymer donor PM6 containing fluorinated thienyl benzodithiophene unit and n-type organic semiconductor acceptor IT-4 F containing fluorinated end-groups were deve...A high performance polymer solar cells(PSCs) based on polymer donor PM6 containing fluorinated thienyl benzodithiophene unit and n-type organic semiconductor acceptor IT-4 F containing fluorinated end-groups were developed. In addition to complementary absorption spectra(300–830 nm) with IT-4 F, the PM6 also has a deep HOMO(the highest occupied molecular) level(-5.50 e V), which will lower the open-circuit voltage(V_(oc)) sacrifice and reduce the E_(loss) of the IT-4 F-based PSCs. Moreover, the strong crystallinity of PM6 is beneficial to form favorable blend morphology and hence to suppress recombination. As a result, in comparison with the PSCs based on a non-fluorinated D/A pair of PBDB-T:ITIC with a medium PCE of 11.2%, the PM6:IT-4 Fbased PSCs yielded an impressive PCE of 13.5% due to the synergistic effect of fluorination on both donor and acceptor, which is among the highest values recorded in the literatures for PSCs to date. Furthermore, a PCE of 12.2% was remained with the active layer thickness of up to 285 nm and a high PCE of 11.4% was also obtained with a large device area of 1 cm^2. In addition, the devices also showed good storage, thermal and illumination stabilities with respect to the efficiency. These results indicate that fluorination is an effective strategy to improve the photovoltaic performance of materials, as well as the both fluorinated donor and acceptor pair-PM6:IT-4 F is an ideal candidate for the large scale roll-to-roll production of efficient PSCs in the future.展开更多
基金This work was supported by the Swedish Research Council(2015-04853,2016-06146,2019-04683)the Swedish Research Council Formas,the Knut and Alice Wallenberg Foundation(2017.0186,2016.0059)+5 种基金the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology,2020-skllmd-07)E.Moons thanks the Swedish Energy Council for financial support(project 48598-1)W.Su thanks the project funded by China Postdoctoral Science Foundation(2020M673054)Postdoctoral Fund of Jinan University,and the National Natural Science Foundation of China(22005121)L.Hou thanks the National Natural Science Foundation of China(61774077)Support from Sino-Danish Centre for Education and Research is fully acknowledged by D.Yu.Y.Li thanks the financial support from the Science and Technology Program of Shanxi Province(2019JQ-244).
文摘The non-fully conjugated polymer as a new class of acceptor materials has shown some advantages over its small molecular counterpart when used in photoactive layers for all-polymer solar cells(all-PSCs),despite a low power conversion efficiency(PCE)caused by its narrow absorption spectra.Herein,a novel non-fully conjugated polymer acceptor PFY-2TS with a low bandgap of~1.40 eV was developed,via polymerizing a largeπ-fused small molecule acceptor(SMA)building block(namely YBO)with a non-conjugated thioalkyl linkage.Compared with its precursor YBO,PFY-2TS retains a similar low bandgap but a higher LUMO level.Moreover,compared with the structural analog of YBO-based fully conjugated polymer acceptor PFY-DTC,PFY-2TS shows a similar absorption spectrum and electron mobility,but significantly different molecular crystallinity and aggregation properties,which results in optimal blend morphology with a polymer donor PBDB-T and physical processes of the device in all-PSCs.As a result,PFY-2TS-based all-PSCs achieved a PCE of 12.31%with a small energy loss of 0.56 eV enabled by the reduced non-radiative energy loss(0.24 eV),which is better than that of 11.08%for the PFY-DTC-based ones.Our work clearly demonstrated that non-fully conjugated polymers as a new class of acceptor materials are very promising for the development of high-performance all-PSCs.
基金supported by the National Natural Science Foundation of China(51422306,51503135,51573120,91633301)Jiangsu Provincial Natural Science Foundation(BK20150332)T.P.Russell was supported by the U.S.Office of Naval Research(N00014-15-1-2244)
文摘A high performance polymer solar cells(PSCs) based on polymer donor PM6 containing fluorinated thienyl benzodithiophene unit and n-type organic semiconductor acceptor IT-4 F containing fluorinated end-groups were developed. In addition to complementary absorption spectra(300–830 nm) with IT-4 F, the PM6 also has a deep HOMO(the highest occupied molecular) level(-5.50 e V), which will lower the open-circuit voltage(V_(oc)) sacrifice and reduce the E_(loss) of the IT-4 F-based PSCs. Moreover, the strong crystallinity of PM6 is beneficial to form favorable blend morphology and hence to suppress recombination. As a result, in comparison with the PSCs based on a non-fluorinated D/A pair of PBDB-T:ITIC with a medium PCE of 11.2%, the PM6:IT-4 Fbased PSCs yielded an impressive PCE of 13.5% due to the synergistic effect of fluorination on both donor and acceptor, which is among the highest values recorded in the literatures for PSCs to date. Furthermore, a PCE of 12.2% was remained with the active layer thickness of up to 285 nm and a high PCE of 11.4% was also obtained with a large device area of 1 cm^2. In addition, the devices also showed good storage, thermal and illumination stabilities with respect to the efficiency. These results indicate that fluorination is an effective strategy to improve the photovoltaic performance of materials, as well as the both fluorinated donor and acceptor pair-PM6:IT-4 F is an ideal candidate for the large scale roll-to-roll production of efficient PSCs in the future.
