High Open Circuit voltage solar cells based on bright mixed halide CsPbBrI2 perovskite nanocrystals synthesized under ambient air conditions

TL;DR

This study demonstrates efficient ambient-air processed mixed halide CsPbBrI2 perovskite nanocrystal solar cells with high open circuit voltage and notable efficiency, highlighting their potential for high-performance photovoltaic applications.

Contribution

First demonstration of high open circuit voltage solar cells using bright mixed halide CsPbBrI2 nanocrystals synthesized under ambient air conditions.

Findings

Solar cells achieved 5.3% efficiency.

Open circuit voltage reached 1.31V.

High PLQY of 65% in films.

Abstract

Lead halide perovskite nanocrystals (NCs) are currently emerging as one of the most interesting solution processed semiconductors since they possess high photoluminescence quantum yield (PLQY), and colour tunability through anion exchange reactions or quantum confinement. Here, we show efficient solar cells based on mixed halide (CsPbBrI2) NCs obtained via anion exchange reactions in ambient conditions. We performed anion exchange reactions in concentrated NC solutions with I-, thus inducing a PL red-shift up to 676 nm, and obtaining a high PLQY in film (65%). Solar cell devices operating in the wavelength range 350-660 nm were fabricated in air with two different deposition methods. The solar cells display a photo-conversion efficiency of 5.3% and open circuit voltage (Voc) up to 1.31V, among the highest reported for perovskite based solar cells with band gap below 2eV, clearly demonstrating the potential of this material.