Direct measurements of band gap grading in polycrystalline CIGS solar cells

TL;DR

This paper introduces a novel measurement technique for directly assessing depth-dependent band gap variations in CIGS solar cells, providing new insights into their electronic properties and efficiency determinants.

Contribution

A new method combining interference and photoluminescence measurements for direct, depth-resolved band gap analysis in CIGS thin-film solar cells.

Findings

Sample-dependent correlation between band gap depth and composition.

Emphasizes importance of direct measurement for accurate analysis.

Provides quantitative insights into electronic properties affecting efficiency.

Abstract

We present direct measurements of depth-resolved band gap variations of CuIn(1-x)Ga(x)Se2 thin-film solar cell absorbers. A new measurement technique combining parallel measurements of local thin-film interference and spectral photoluminescence was developed for this purpose. We find sample-dependent correlation parameters between measured band gap depth and composition profiles, and emphasize the importance of direct measurements. These results bring a quantitative insight into the electronic properties of the solar cells and open a new way to analyze parameters that determine the efficiency of solar cells.