Ternary organic photovoltaic (OPV) devices with multiple light-absorbing active materials have emerged as an efficient strategy for realizing further improvements in the power conversion efficiency (PCE) without building complex multijunction structures. However, the third component often acts as recombination centers and, hence, the optimization of ternary blend morphology poses a major challenge to improving the PCE of these devices. In this work, the performance of OPVs is enhanced through the morphological modification of nonfullerene acceptor (NFA)-containing binary active layers. This modification is achieved by incorporating fullerenes into the layers. The uniformly dispersed fullerenes are sufficiently continuous and successfully mediate the ordering of NFA without charge or energy transfer. Owing to the simultaneous improvement in the charge generation and extraction, the PCE (12.1%) of these parallel-linked ternary devices is considerably higher than those of the corresponding binary devices (9.95% and 7.78%). Moreover, the additional energy loss of the ternary device is minimized, compared with that of the NFA-based binary device, due to the judicious control of the effective donor:acceptor composition of the ternary blends.
Bibliographical noteFunding Information:
W.T.H. and F.T.A.W. contributed equally to this work. The authors gratefully acknowledge support from the New and Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resources from the Ministry of Trade, Industry and Energy, Republic of Korea (Grant No. 20163030013960), the National Research Foundation (NRF) Grant funded by the Korean Government (MSIP, Grant Nos. 2016R1A5A1012966 and 2017R1A2B2009178), and the Global Scholarship Program for Foreign Graduate Students at Kookmin University in Korea.
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics