Inverted perovskite solar cells with inserted cross-linked electron-blocking interlayers for performance enhancement

Perovskite solar cells fabricated via a solution process have drawn great attention due to their high power conversion efficiency (PCE). Here, we report cross-linked anode interlayers with solvent-resistance that reduce electron-hole recombination by blocking electrons for inverted type solution processed perovskite solar cells. The cross-linkable materials used are (N,N'-bis(4-(6-((3-ethyloxetan-3-yl)-methoxy)-hexyloxy) phenyl)-N,N'-bis(4-methoxyphenyl)biphenyl-4,4'-diamine (QUPD) and N,N'-bis(4-(6-(( 3-ethyloxetan-3-yl) methoxy))-hexylphenyl)-N,N'-diphenyl-4,4'-diamine (OTPD)), which can be cross-linked in the presence of acid groups provided by diffusion from the underlying PEDOT:PSS layer. The resulting PCE shows an improvement from 9.93% (control device) to 13.06% (cross-linked QUPD (X-QUPD)) by about 3% under AM 1.5G 100 mW cm(-2) illumination, which demonstrates that the introduction of cross-linked electron blocking interlayers is a promising way to enhance the performance of inverted type solution processed perovskite solar cells.