The Potential of Geminate Pairs in Lead Halide Perovskite revealed via Time-resolved Photoluminescence

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Hauptverfasser: Hempel, Hannes, Stolterfoht, Martin, Karalis, Orestis, Unold, Thomas
Format: Preprint
Veröffentlicht: 2024
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author Hempel, Hannes
Stolterfoht, Martin
Karalis, Orestis
Unold, Thomas
author_facet Hempel, Hannes
Stolterfoht, Martin
Karalis, Orestis
Unold, Thomas
contents Photoluminescence (PL) under continuous illumination is commonly employed to assess voltage losses in solar energy conversion materials. However, the early temporal evolution of these losses remains poorly understood. Therefore, we extend the methodology to time-resolved PL, introducing the concepts of geminate PL, doping PL, and sibling PL to quantify the transient chemical potential of photogenerated electron-hole pairs and key optoelectronic properties. Analyzing the initial PL amplitudes reveals hot charge carrier separation for around 100 nm and is likely limited by the grain size of the triple cation perovskite. The following PL decay is caused by the diffusive separation of non-excitonic geminate pairs and time-resolves a fundamental yet often overlooked energy loss by increasing entropy. For triple-cation halide perovskite, we measure a "geminate correlation energy" of up to 90 meV, persisting for ~ten nanoseconds. This energy is unutilized in standard solar cells and is considered lost in the Shockley-Queisser model. Therefore, this geminate energy could substantially enhance the device's efficiency, particularly under maximum power point and low-illumination conditions.
format Preprint
id arxiv_https___arxiv_org_abs_2409_06382
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Potential of Geminate Pairs in Lead Halide Perovskite revealed via Time-resolved Photoluminescence
Hempel, Hannes
Stolterfoht, Martin
Karalis, Orestis
Unold, Thomas
Materials Science
Applied Physics
Photoluminescence (PL) under continuous illumination is commonly employed to assess voltage losses in solar energy conversion materials. However, the early temporal evolution of these losses remains poorly understood. Therefore, we extend the methodology to time-resolved PL, introducing the concepts of geminate PL, doping PL, and sibling PL to quantify the transient chemical potential of photogenerated electron-hole pairs and key optoelectronic properties. Analyzing the initial PL amplitudes reveals hot charge carrier separation for around 100 nm and is likely limited by the grain size of the triple cation perovskite. The following PL decay is caused by the diffusive separation of non-excitonic geminate pairs and time-resolves a fundamental yet often overlooked energy loss by increasing entropy. For triple-cation halide perovskite, we measure a "geminate correlation energy" of up to 90 meV, persisting for ~ten nanoseconds. This energy is unutilized in standard solar cells and is considered lost in the Shockley-Queisser model. Therefore, this geminate energy could substantially enhance the device's efficiency, particularly under maximum power point and low-illumination conditions.
title The Potential of Geminate Pairs in Lead Halide Perovskite revealed via Time-resolved Photoluminescence
topic Materials Science
Applied Physics
url https://arxiv.org/abs/2409.06382