Constructing Ultra‐Shallow Near‐Edge States for Efficient and Stable Perovskite Solar Cells

Abstract

Electronic band structure engineering of metal‐halide perovskites (MHP) lies at the core of fundamental materials research and photovoltaic applications. However, reconfiguring the band structures in MHP for optimized electronic properties remains challenging. Here, we report a generic strategy for constructing near‐edge states to improve carrier properties, leading to enhanced device performances. The near‐edge states are designed around the valence band edge using theoretical prediction and constructed through tailored material engineering. These states are experimentally revealed with activation energies of around 23 milli‐electron volts by temperature‐dependent time‐resolved spectroscopy. Such small activation energies enable prolonged carrier lifetime with efficient carrier transition dynamics and low non‐radiative recombination losses, as corroborated by the millisecond lifetimes of microwave conductivity. By constructing near‐edge states in positive‐intrinsic‐negative inverted cells, we achieve a champion efficiency of 25.4% (25.0% certified) for a 0.07‐cm2 cell and 23.6% (22.7% certified) for a 1‐cm2 cell. The most stable encapsulated cell retains 90% of its initial efficiency after 1,100 hours of maximum power point tracking under one sun illumination (100 mW/cm2) at 65 °C in ambient air.This article is protected by copyright. All rights reserved

Stabilizing Lead Halide Perovskites via an Organometallic Chemical Bridge for Efficient and Stable Photovoltaics

“…Similarly, FcP 2 and perovskite formed a binding energy of 3.89 eV in two adjacent slabs, suggesting that FcP 2 could chelate, bind, and theoretically bridge perovskite interfaces . From the corresponding electronic partial density of states (PDOS) in Figure S5, we observe the emergence of highly hybridized Fe electronic orbitals appearing about the Fermi energy level and large sp 3 hybridization between FcP 2 and FAPbI 3 surface orbitals when the FcP 2 molecule absorbs on the PbI 2 termination surface …”