Dimeric Carbazole Core Based Dopant‐Free Hole Transport Material for N‐i‐p Planar Perovskite Solar Cell

A profitable approach for improving the stability of n-i-p planar perovskite solar cell (PSC) is developing dopant-free hole transport materials (HTMs) with desirable intrinsic charge transport properties. In this work, by adopting a metal-free catalytic intramolecular C & horbar;C coupling reaction, a carbazole dimer-based fused-ring is synthesized, and further developed a small molecular dopant-free HTM abbreviated as NCz-DM with appropriate energy level, excellent hole transport and film formation properties. Applied in n-i-p planar PSC, an impressive power conversion efficiency (PCE) of 24.0% is achieved, together with enhanced humidity, thermal and light stability, which is among the high level of ever-reported results for PSCs utilizing small molecular dopant-free HTM. A dimeric carbazole-based fused-ring (NCz) is synthesized through a metal-free catalytic intramolecular C-C coupling reaction, and a novel dopant-free hole transport material (HTM) NCz-DM based on NCz core unit is further developed, achieving an impressive efficiency of 24.0%. image