Pitfalls and prospects of optical spectroscopy to characterize perovskite-transport layer interfaces

TL;DR

This paper reviews how optical spectroscopy techniques can be used to evaluate and improve the interfaces between perovskite layers and transport layers in solar cells, aiming to enhance efficiency and stability.

Contribution

It critically examines optical spectroscopy methods for interface characterization and provides guidelines for interpreting measurements to optimize device performance.

Findings

Combining cw and time-resolved PL reveals non-radiative losses.

Transient spectroscopies assess potential for loss-less carrier extraction.

Recommendations help extrapolate optical data to device efficiency improvements.

Abstract

Perovskite photovoltaics has witnessed an unprecedented increase in power conversion efficiency over the last decade. The choice of transport layers, through which photo-generated electrons and holes are transported to the electrodes, is a crucial factor for further improving both the device performance and stability. In this perspective, we critically examine the application of optical spectroscopy to characterize the quality of the transport layer-perovskite interface. We highlight the power of complementary studies that use both continuous wave (cw) and time-resolved photoluminescence (PL) to understand non-radiative losses, and additional transient spectroscopies for characterizing the potential for loss-less carrier extraction at the solar cell interfaces. Based on this discussion, we make recommendations on how to extrapolate results from optical measurements to assess the quality of a transport layer, and its impact on solar cell efficiency.