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Enabling High‐Performance Tandem Organic Photovoltaic Cells by Balancing the Front and Rear Subcells
Author(s) -
Cheng Pei,
Wang HaoCheng,
Zheng Ran,
Zhu Yuan,
Dai Shuixing,
Li Zeyuan,
Chen ChungHao,
Zhao Yepin,
Wang Rui,
Meng Dong,
Zhu Chenhui,
Wei KungHwa,
Zhan Xiaowei,
Yang Yang
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202002315
Subject(s) - materials science , tandem , optoelectronics , organic solar cell , photovoltaic system , open circuit voltage , band gap , energy conversion efficiency , photovoltaics , exciton , absorption (acoustics) , voltage , short circuit , polymer , electrical engineering , composite material , physics , quantum mechanics , engineering
In tandem organic photovoltaics, the front subcell is based on large‐bandgap materials, whereas the case of the rear subcell is more complicated. The rear subcell is generally composed of a narrow‐bandgap acceptor for infrared absorption but a large‐bandgap donor to realize a high open‐circuit voltage. Unfortunately, most of the ultraviolet–visible part of the photons are absorbed by the front subcell; as a result, in the rear subcell, the number of excitons generated on large‐bandgap donors will be reduced significantly. This reduces the (photo) conductivity and finally limits the hole‐transporting property of the rear subcell. In this work, a simple and effective way is proposed to resolve this critical issue. To ensure sufficient photogenerated holes in the rear subcell, a small amount of an infrared‐absorbing polymer donor as a third component is introduced, which provides a second hole‐generation and transporting mechanism to minimize the aforementioned detrimental effects. Finally, the short‐circuit current density of the two‐terminal tandem organic photovoltaic is significantly enhanced from 10.3 to 11.7 mA cm −2 (while retaining the open‐circuit voltage and fill factor) to result in an enhanced power conversion efficiency of 15.1%.