High Photovoltaic Efficiency in Bulk-Stacked One-Dimensional GeSe$_{2}$ van der Waals Crystal

Fuente: arXiv
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Autori principali: Kang, Seoung-Hun, Kim, Youngjae, Jang, Bo Gyu, Kim, Sejoong
Natura: Preprint
Pubblicazione: 2026
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author Kang, Seoung-Hun
Kim, Youngjae
Jang, Bo Gyu
Kim, Sejoong
author_facet Kang, Seoung-Hun
Kim, Youngjae
Jang, Bo Gyu
Kim, Sejoong
contents Germanium diselenide (GeSe$_{2}$) has recently attracted substantial interest as a rare example of one-dimensional (1D) van der Waals material. Here, we investigate the photovoltaic potential of bulk-stacked GeSe$_{2}$ chains using first-principles calculations within the $GW0$ approximation and the Bethe-Salpeter equation (BSE) to capture quasiparticle and excitonic effects. The bulk GeSe$_{2}$ exhibits indirect GW band gaps of 1.92 eV (type-I) and 1.08 eV (type-II). Optical calculations show markedly stronger visible-light absorption in type-II, yielding a spectroscopically limited maximum efficiency (SLME) of ~25.6% at a 0.5 $μ$m thickness. Phonon and room-temperature ab initio molecular dynamics analyses indicate that type-II is dynamically stable, whereas type-I shows imaginary phonon modes, suggesting a propensity for structural distortion. These results identify type-II GeSe2 as a promising stable absorber for thin-film photovoltaics with enhanced flexibility compared to typical 2D vdW systems.
format Preprint
id arxiv_https___arxiv_org_abs_2602_09688
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle High Photovoltaic Efficiency in Bulk-Stacked One-Dimensional GeSe$_{2}$ van der Waals Crystal
Kang, Seoung-Hun
Kim, Youngjae
Jang, Bo Gyu
Kim, Sejoong
Materials Science
Germanium diselenide (GeSe$_{2}$) has recently attracted substantial interest as a rare example of one-dimensional (1D) van der Waals material. Here, we investigate the photovoltaic potential of bulk-stacked GeSe$_{2}$ chains using first-principles calculations within the $GW0$ approximation and the Bethe-Salpeter equation (BSE) to capture quasiparticle and excitonic effects. The bulk GeSe$_{2}$ exhibits indirect GW band gaps of 1.92 eV (type-I) and 1.08 eV (type-II). Optical calculations show markedly stronger visible-light absorption in type-II, yielding a spectroscopically limited maximum efficiency (SLME) of ~25.6% at a 0.5 $μ$m thickness. Phonon and room-temperature ab initio molecular dynamics analyses indicate that type-II is dynamically stable, whereas type-I shows imaginary phonon modes, suggesting a propensity for structural distortion. These results identify type-II GeSe2 as a promising stable absorber for thin-film photovoltaics with enhanced flexibility compared to typical 2D vdW systems.
title High Photovoltaic Efficiency in Bulk-Stacked One-Dimensional GeSe$_{2}$ van der Waals Crystal
topic Materials Science
url https://arxiv.org/abs/2602.09688