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arXiv · 2306.11311

Laser-Annealing and Solid-Phase Epitaxy of Selenium Thin-Film Solar Cells

Rasmus Nielsen·Tobias H. Hemmingsen·Tobias G. Bonczyk·Ole Hansen·Ib Chorkendorff·Peter C. K. Vesborg
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Abstract

Selenium has resurged as a promising photovoltaic material in solar cell research due to its wide direct bandgap of 1.95 eV, making it a suitable candidate for a top cell in tandem photovoltaic devices. However, the optoelectronic quality of selenium thin-films has been identified as a key bottleneck for realizing high-efficiency selenium solar cells. In this study, we present a novel approach for crystallizing selenium thin-films using laser-annealing as an alternative to the conventionally used thermal annealing strategy. By laser-annealing through a semitransparent substrate, a buried layer of high-quality selenium crystallites is formed and used as a growth template for solid-phase epitaxy. The resulting selenium thin-films feature larger and more preferentially oriented grains with a negligible surface roughness in comparison to thermally annealed selenium thin-films. We fabricate photovoltaic devices using this strategy, and demonstrate a record ideality factor of n=1.37, a record fill factor of FF=63.7%, and a power conversion efficiency of PCE=5.0%. The presented laser-annealing strategy is universally applicable and is a promising approach for crystallizing a wide range of photovoltaic materials where high temperatures are needed while maintaining a low substrate temperature.

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BibTeXRIS

Rasmus Nielsen, Tobias H. Hemmingsen, Tobias G. Bonczyk, Ole Hansen, Ib Chorkendorff, Peter C. K. Vesborg. 2023-06-20. Laser-Annealing and Solid-Phase Epitaxy of Selenium Thin-Film Solar Cells. https://doi.org/10.1021/acsaem.3c01464

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