The spatial collection efficiency of photogenerated charge carriers in photovoltaic and photoelectrochemical devices

TL;DR

This paper discusses a method to empirically determine the spatial collection efficiency of photogenerated charge carriers in photovoltaic and photoelectrochemical devices, highlighting its potential for studying new materials and aiding device design.

Contribution

It introduces the application of a simple, empirical method to extract spatial collection efficiency in stratified devices, including unconventional materials like metal-oxide semiconductors.

Findings

Method allows empirical extraction of spatial collection efficiency

Applicable to operando performance characterization

Facilitates analysis of new and complex materials

Abstract

The spatial collection efficiency portrays the driving forces and loss mechanisms in photovoltaic and photoelectrochemical devices. It is defined as the fraction of photogenerated charge carriers created at a specific point within the device that contribute to the photocurrent. In stratified planar structures, the spatial collection efficiency can be extracted out of photocurrent action spectra measurements empirically, with few a priori assumptions. Although this method was applied to photovoltaic cells made of well-understood materials, it has never been used to study unconventional materials such as metal-oxide semiconductors that are often employed in photoelectrochemical cells. This perspective shows the opportunities that this method has to offer for investigating new materials and devices with unknown properties. The relative simplicity of the method, and its applicability to operando performance characterization, makes it an important tool for analysis and design of new photovoltaic and photoelectrochemical materials and devices.