Minimizing buried interfacial defects for efficient inverted perovskite solar cells

TLDR

Controlling perovskite morphology and defects at the buried perovskite‑substrate interface remains challenging for inverted perovskite solar cells. The study reports an amphiphilic molecular hole transporter that forms a superwetting underlayer, enabling high‑quality perovskite films with minimized buried‑interface defects. The transporter, featuring a multifunctional cyanovinyl phosphonic acid group, creates a superwetting underlayer for perovskite deposition, thereby improving film quality. The resulting perovskite film exhibited a 17 % photoluminescence quantum yield, a Shockley‑Read‑Hall lifetime of ~7 µs, and enabled certified power‑conversion efficiencies of 25.4 % (1 cm² cells 23.4 % and 10 cm² modules 22.0 %) with 1.21 V open‑circuit voltage and 84.7 % fill factor, while encapsulated modules remained stable under operational and damp‑heat conditions.

Abstract

Controlling the perovskite morphology and defects at the buried perovskite-substrate interface is challenging for inverted perovskite solar cells. In this work, we report an amphiphilic molecular hole transporter, (2-(4-(bis(4-methoxyphenyl)amino)phenyl)-1-cyanovinyl)phosphonic acid, that features a multifunctional cyanovinyl phosphonic acid group and forms a superwetting underlayer for perovskite deposition, which enables high-quality perovskite films with minimized defects at the buried interface. The resulting perovskite film has a photoluminescence quantum yield of 17% and a Shockley-Read-Hall lifetime of nearly 7 microseconds and achieved a certified power conversion efficiency (PCE) of 25.4% with an open-circuit voltage of 1.21 volts and a fill factor of 84.7%. In addition, 1-square centimeter cells and 10-square centimeter minimodules show PCEs of 23.4 and 22.0%, respectively. Encapsulated modules exhibited high stability under both operational and damp heat test conditions.