Pinhole induced efficiency variation in perovskite solar cells

TL;DR

This paper investigates how pinholes influence the efficiency of perovskite solar cells through numerical simulations, revealing differential effects on current and voltage, and proposes a method to estimate surface coverage.

Contribution

It provides new insights into the impact of pinhole size distribution on cell performance and introduces a simple technique to estimate surface coverage.

Findings

Pinhole size distribution significantly affects short circuit current.

Open circuit voltage is only nominally affected by pinholes.

Interface engineering can mitigate efficiency loss due to pinholes.

Abstract

Process induced efficiency variation is a major concern for all thin film solar cells, including the emerging perovskite based solar cells. In this manuscript, we address the effect of pinholes or process induced surface coverage aspects on the efficiency of such solar cells through detailed numerical simulations. Interestingly, we find the pinhole size distribution affects the short circuit current and open circuit voltage in contrasting manners. Specifically, while the Jsc is heavily dependent on the pinhole size distribution, surprisingly, the Voc seems to be only nominally affected by it. Further, our simulations also indicate that, with appropriate interface engineering, it is indeed possible to design a nanostructured device with efficiencies comparable to that of ideal planar structures. Additionally, we propose a simple technique based on terminal IV characteristics to estimate the surface coverage in perovskite solar cells.