Molecular Engineering for Two-Dimensional Perovskites with Photovoltaic Efficiency Exceeding 18%

By Guangbao Wu, Tinghuan Yang, Xing Li, Nafees Ahmad, Xuning Zhang, S. Yue, Jin Zhou, Yanxun Li, Hui Wang, Xinghua Shi and 4 more. 2020

177 citations recorded by the source corpus.

Summary Two-dimensional (2D) perovskites with excellent stability and optoelectronic properties have aroused great interest for use in perovskite solar cells (PSCs). To date, the power conversion efficiencies (PCEs) of state-of-the art 2D-PSCs are non-satisfactory because of higher recombination losses in 2D quantum wells. Here, based on a series of alkylic ammonium spacers (ethylamine to hexylamine) with different chain lengths, we present a strategy via the molecular van der Waals interaction to realize modified crystallization, phase distribution, and quantum-confined behaviors in Ruddlesden-Popper 2D perovskites (n = 4). With the optimal amylamine (AA) spacer, high-quality 2D perovskites featuring well-aligned phase alignments with fewer unfavorable n-value species and a reduced exciton binding energy have been realized, leading to sufficient charge transfers through different n-value components. The devices based on (AA)2MA3Pb4I13 yield a champion PCE of 18.42%, showing an impressive open-circuit voltage of 1.25 V and a fill factor exceeding 0.80.

Subfields: Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/4f7c8451f1b8a68ae688669f57a7c3d9731a0c17