Eliminating the Electric Field Response in a Perovskite Heterojunction Solar Cell to Improve Operational Stability

TL;DR

This paper introduces a heterojunction design with a heavily doped p+ layer to suppress electric field response and ion migration in perovskite solar cells, significantly enhancing their operational stability.

Contribution

The study proposes a novel heterojunction approach using a p+ layer to eliminate electric field effects in perovskite absorbers, improving stability and feasibility for practical use.

Findings

Heterojunction reduces electric field response in perovskite cells.

Suppression of ion migration enhances operational stability.

p+ layer is defect-tolerant and adaptable to various materials.

Abstract

Intrinsic and extrinsic ion migration is a very large threat to the operational stability of perovskite solar cells and is difficult to completely eliminate due to the low activation energy of ion migration and the existence of internal electric field. We propose a heterojunction route to help suppress ion migration, thus improving the operational stability of the cell from the perspective of eliminating the electric field response in the perovskite absorber. A heavily doped p-type (p+) thin layer semiconductor is introduced between the electron transporting layer (ETL) and perovskite absorber. The heterojunction charge depletion and electric field are limited to the ETL and p+ layers, while the perovskite absorber and hole transporting layer remain neutral. The p+ layer has a variety of candidate materials and is tolerant of defect density and carrier mobility, which makes this heterojunction route highly feasible and promising for use in practical applications.