Gao Wei, Qi Feng, Peng Zhengxing, Lin Francis R, Jiang Kui, Zhong Cheng, Kaminsky Werner, Guan Zhiqiang, Lee Chun-Sing, Marks Tobin J, Ade Harald, Jen Alex K-Y
Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong.
Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon, 999077, Hong Kong.
Adv Mater. 2022 Aug;34(32):e2202089. doi: 10.1002/adma.202202089. Epub 2022 Jul 11.
A record power conversion efficiency (PCE) of over 19% is realized in planar-mixed heterojunction (PMHJ) organic solar cells (OSCs) by adopting the asymmetric selenium substitution strategy in making a pseudosymmetric electron acceptor, BS3TSe-4F. The combined molecular asymmetry with more polarizable selenium substitution increases the dielectric constant of the D18/BS3TSe-4F blend, helping lower the exciton binding energy. On the other hand, dimer packing in BS3TSe-4F is facilitated to enable free charge generation, helping more efficient exciton dissociation and lowering the radiative recombination loss (ΔE ) of OSCs. As a result, PMHJ OSCs based on D18/BS3TSe-4F achieve a PCE of 18.48%. By incorporating another mid-bandgap acceptor Y6-O into D18/BS3TSe-4F to form a ternary PMHJ, a higher open-circuit voltage (V ) can be achieved to realize an impressive PCE of 19.03%. The findings of using pseudosymmetric electron acceptors in enhancing device efficiency provides an effective way to develop highly efficient acceptor materials for OSCs.
通过在制备伪对称电子受体BS3TSe-4F时采用不对称硒取代策略，平面混合异质结（PMHJ）有机太阳能电池（OSC）实现了超过19%的创纪录功率转换效率（PCE）。分子不对称性与更具极化性的硒取代相结合，提高了D18/BS3TSe-4F共混物的介电常数，有助于降低激子结合能。另一方面，促进了BS3TSe-4F中的二聚体堆积以实现自由电荷产生，有助于更有效地激子解离并降低OSC的辐射复合损失（ΔE）。结果，基于D18/BS3TSe-4F的PMHJ OSC实现了18.48%的PCE。通过将另一种中带隙受体Y6-O掺入D18/BS3TSe-4F中以形成三元PMHJ，可以实现更高的开路电压（V），从而实现令人印象深刻的19.03%的PCE。使用伪对称电子受体提高器件效率的研究结果为开发用于OSC的高效受体材料提供了一种有效方法。
