Yangwei Shi1,Declan McCarthy2,Kevin Ho1,Fangyuan Jiang1,Stephen Barlow2,Seth Marder2,David Ginger1
University of Washington1,Georgia Institute of Technology2
Yangwei Shi1,Declan McCarthy2,Kevin Ho1,Fangyuan Jiang1,Stephen Barlow2,Seth Marder2,David Ginger1
University of Washington1,Georgia Institute of Technology2
Organic-inorganic halide perovskite has demonstrated great potential in application of photovoltaics with power conversion efficiency (PCE) surging from 3.8% to current record efficiency of 25.7% for a single junction perovskite solar cell. The start-of-art perovskite solar cell usually adopts inorganic metal oxide such as TiO<sub>2</sub>, SnO<sub>2</sub> as electron transport layers (ETLs). However, these ETLs generally require high annealing temperature and can cause instability issues due to their photocatalytic nature. Here we report a photo-crosslinkable naphthalene diimide (NDI) polymer with a cinnamate side chain as ETL for solution processed n-i-p perovskite solar cells. Our solar cell device results show that crosslinked NDI polymer exhibit better VOC, FF, PCE, and less hysteresis than its non-crosslinked counterpart. We ascribe this PCE increase to improved perovskite crystallinity and energy level alignment, reduced nonradiative recombination and series resistance of the crosslinked NDI polymer-based perovskite solar cells.