In-depth photoluminescence analysis of Cu2GeS3 microcrystals under pulsed and continuous-wave excitation

In this study, an in-depth photoluminescence (PL) analysis of Cu _2 GeS _3 microcrystals under pulsed and continuous-wave (CW) excitation is performed to explore the optical properties and defect structure of this promising novel absorber material for indoor photovoltaics. A rich low-temperature ( T...

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Main Authors: Jüri Krustok, Joel Kokla, Reelika Kaupmees, Maarja Grossberg-Kuusk, Marit Kauk-Kuusik
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:JPhys Energy
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Online Access:https://doi.org/10.1088/2515-7655/adc836
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author Jüri Krustok
Joel Kokla
Reelika Kaupmees
Maarja Grossberg-Kuusk
Marit Kauk-Kuusik
author_facet Jüri Krustok
Joel Kokla
Reelika Kaupmees
Maarja Grossberg-Kuusk
Marit Kauk-Kuusik
author_sort Jüri Krustok
collection DOAJ
description In this study, an in-depth photoluminescence (PL) analysis of Cu _2 GeS _3 microcrystals under pulsed and continuous-wave (CW) excitation is performed to explore the optical properties and defect structure of this promising novel absorber material for indoor photovoltaics. A rich low-temperature ( T = 8 K) PL spectra with multiple peaks was detected by both excitation sources and analyzed in detail. The edge emission, including free and bound excitons as well as unique trion emission at 1.575 eV, which becomes dominant under the pulsed laser excitation, enabling clear detection of its properties. At higher temperatures also band-to-band emission is observed under the CW excitation, and the donor-acceptor pair recombination with its phonon replica is dominating the PL spectra revealing a shallow donor defect with an ionization energy of 35 meV and a slightly deep acceptor defect with an ionization energy of 119 meV. In addition, from the temperature dependencies of the PL peaks, an extremely weak electron-phonon coupling in CGS was found. The observed edge emission and detected rather shallow defects emphasize the high crystalline quality and the suitability of Cu _2 GeS _3 for photovoltaic applications.
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spelling doaj-art-a9e8e55a0f7943b7ab8c2c56e4ffe2f82025-08-20T02:11:34ZengIOP PublishingJPhys Energy2515-76552025-01-017303500310.1088/2515-7655/adc836In-depth photoluminescence analysis of Cu2GeS3 microcrystals under pulsed and continuous-wave excitationJüri Krustok0https://orcid.org/0000-0002-4671-2332Joel Kokla1https://orcid.org/0009-0003-9022-201XReelika Kaupmees2https://orcid.org/0000-0002-1766-4837Maarja Grossberg-Kuusk3https://orcid.org/0000-0003-3357-189XMarit Kauk-Kuusik4https://orcid.org/0000-0003-0071-8568Department of Materials and Environmental Technology, Tallinn University of Technology , Ehitajate tee 5, 19086 Tallinn, EstoniaDepartment of Materials and Environmental Technology, Tallinn University of Technology , Ehitajate tee 5, 19086 Tallinn, EstoniaDepartment of Materials and Environmental Technology, Tallinn University of Technology , Ehitajate tee 5, 19086 Tallinn, EstoniaDepartment of Materials and Environmental Technology, Tallinn University of Technology , Ehitajate tee 5, 19086 Tallinn, EstoniaDepartment of Materials and Environmental Technology, Tallinn University of Technology , Ehitajate tee 5, 19086 Tallinn, EstoniaIn this study, an in-depth photoluminescence (PL) analysis of Cu _2 GeS _3 microcrystals under pulsed and continuous-wave (CW) excitation is performed to explore the optical properties and defect structure of this promising novel absorber material for indoor photovoltaics. A rich low-temperature ( T = 8 K) PL spectra with multiple peaks was detected by both excitation sources and analyzed in detail. The edge emission, including free and bound excitons as well as unique trion emission at 1.575 eV, which becomes dominant under the pulsed laser excitation, enabling clear detection of its properties. At higher temperatures also band-to-band emission is observed under the CW excitation, and the donor-acceptor pair recombination with its phonon replica is dominating the PL spectra revealing a shallow donor defect with an ionization energy of 35 meV and a slightly deep acceptor defect with an ionization energy of 119 meV. In addition, from the temperature dependencies of the PL peaks, an extremely weak electron-phonon coupling in CGS was found. The observed edge emission and detected rather shallow defects emphasize the high crystalline quality and the suitability of Cu _2 GeS _3 for photovoltaic applications.https://doi.org/10.1088/2515-7655/adc836photoluminescenceexcitonstrionsCW laserpulsed laserDA pairs
spellingShingle Jüri Krustok
Joel Kokla
Reelika Kaupmees
Maarja Grossberg-Kuusk
Marit Kauk-Kuusik
In-depth photoluminescence analysis of Cu2GeS3 microcrystals under pulsed and continuous-wave excitation
JPhys Energy
photoluminescence
excitons
trions
CW laser
pulsed laser
DA pairs
title In-depth photoluminescence analysis of Cu2GeS3 microcrystals under pulsed and continuous-wave excitation
title_full In-depth photoluminescence analysis of Cu2GeS3 microcrystals under pulsed and continuous-wave excitation
title_fullStr In-depth photoluminescence analysis of Cu2GeS3 microcrystals under pulsed and continuous-wave excitation
title_full_unstemmed In-depth photoluminescence analysis of Cu2GeS3 microcrystals under pulsed and continuous-wave excitation
title_short In-depth photoluminescence analysis of Cu2GeS3 microcrystals under pulsed and continuous-wave excitation
title_sort in depth photoluminescence analysis of cu2ges3 microcrystals under pulsed and continuous wave excitation
topic photoluminescence
excitons
trions
CW laser
pulsed laser
DA pairs
url https://doi.org/10.1088/2515-7655/adc836
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