Performance limitations in thieno[3,4-c]pyrrole-4,6-dione-based polymer:ITIC solar cells

We report a systematic study of the efficiency limitations of non-fullerene organic solar cells that exhibit a small energy loss (Eloss) between the polymer donor and the non-fullerene acceptor. To clarify the impact of Eloss on the performance of the solar cells, three thieno[3,4-c]pyrrole-4,6-dione-based conjugated polymers (PTPD3T, PTPD2T, and PTPDBDT) are employed as the electron donor, which all have complementary absorption spectra compared with the ITIC acceptor. The corresponding photovoltaic devices show that low Eloss (0.54 eV) in PTPDBDT:ITIC leads to a high open-circuit voltage (Voc) of 1.05 V, but also to a small quantum efficiency, and in turn photocurrent. The high Voc or small energy loss in the PTPDBDT-based solar cells is a consequence of less non-radiative recombination, whereas the low quantum efficiency is attributed to the unfavorable micro-phase separation, as confirmed by the steady-state and time-resolved photoluminescence experiments, grazing-incidence wide-angle X-ray scattering, and resonant soft X-ray scattering (R-SoXS) measurements. We conclude that to achieve high performance non-fullerene solar cells, it is essential to realize a large Voc with small Eloss while simultaneously maintaining a high quantum efficiency by manipulating the molecular interaction in the bulk-heterojunction.

Citation

Yang F, Qian D, Balawi AH, Wu Y, Ma W, et al. (2017) Performance limitations in thieno[3,4-c]pyrrole-4,6-dione-based polymer:ITIC solar cells. Physical Chemistry Chemical Physics 19: 23990–23998. Available: http://dx.doi.org/10.1039/c7cp04780k.

Sponsors

We are thankful for the support from the Ministry of science and technology (No. 2016YFA0200700). We thank Mr Qiang Wang and Mr Ralf Bovee at Eindhoven University of Technology for GPC analysis, Dr Cheng Wang and Dr Chenhui Zhu from Lawrence Berkeley National Laboratory for GIWAXS and R-SoXS measurement, Prof. Yi Zhou and Prof. Yongfang Li at Soochow University for steady state PL measurement, and Dr Xianjie Liu at Linköping University for UPS measurement. This work was supported by the Recruitment Program of Global Youth Experts of China. The work was further supported by the National Natural Science Foundation of China (21574138, 91233205, and 91633301) and the Strategic Priority Research Program (XDB12030200) of the Chinese Academy of Sciences. D. Q. and F. Z. acknowledge financial support from the Swedish Research Council (VR621-2013-5561) and the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU No 200900971). X-ray data were acquired at beamlines 7.3.3 and 11.0.1.2 at the Advanced Light Source, which is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Z. T. acknowledges financial support from the Alexander-von-Humboldt foundation. The research reported in this publication was supported by the funding from the King Abdullah University of Science and Technology (KAUST).