From optical pumping to electrical pumping: the threshold overestimation in metal halide perovskites

Qin, Jiajun; Tang, Yang; Zhang, Jia; Sheng, Tangyao; Karlsson, Max; Zhang, Tiankai; Cai, Wangfeng; Shi, Lei; Ni, Wen‐Xiu; Gao, Feng

doi:10.1039/d2mh01382g

Cited by 11 publications

(5 citation statements)

References 38 publications

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“…10,11 Many-body effects and strong Coulomb interactions occurring after photoexcitation lead to intrinsic bandgap shrinking. 12,13 Although this phenomenon is commonly observed in various semiconductor materials, its overall behaviour is dictated by the competition among several different effects, and the exact origin and mechanism remain unclear. Transient spectroscopic characteristics induced by femtosecond (fs) pump and probe laser In this study, we have demonstrated the significant role of phonons in the photo-induced transient bandgap renormalization (BGR) of MAPbBr 3 perovskite single crystals, in addition to the contribution from photogenerated hot carriers.…”

Section: Introductionmentioning

confidence: 99%

Phonon-driven transient bandgap renormalization in perovskite single crystals

Wang¹,

Wang²,

Nughays³

et al. 2023

Mater. Horiz.

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Section: Introductionmentioning

confidence: 99%

Phonon-driven transient bandgap renormalization in perovskite single crystals

Wang¹,

Wang²,

Nughays³

et al. 2023

Mater. Horiz.

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“…Also, a weak positive signal promptly appears at subpicosecond time scales on the lower-energy side of the optical gap, which is attributed to band gap renormalization (BGR). The origin of these transient signals in the visible region has been extensively discussed previously. ,,− It is worth noting that the negative peak at 2.35 eV undergoes a red shift at early times, which can be attributed to the interplay between the red shift due to BGR and the blue shift resulting from the Burstein–Moss effect (see Figures S4 and S5 for the normalized spectral traces and time traces, Supporting Information). However, it has been reported that under band edge excitation, inorganic perovskite nanocrystals induce a transient blue shift attributed to polaron formation on the 300 fs time scale. , …”

Section: Resultsmentioning

confidence: 99%

Disentangling Thermal from Electronic Contributions in the Spectral Response of Photoexcited Perovskite Materials

Wang,

Nughays,

Rossi

et al. 2024

J. Am. Chem. Soc.

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Disentangling electronic and thermal effects in photoexcited perovskite materials is crucial for photovoltaic and optoelectronic applications but remains a challenge due to their intertwined nature in both the time and energy domains. In this study, we employed temperature-dependent variable-angle spectroscopic ellipsometry, density functional theory calculations, and broadband transient absorption spectroscopy spanning the visible to mid-to-deep-ultraviolet (UV) ranges on MAPbBr 3 thin films. The use of deep-UV detection opens a new spectral window that enables the exploration of high-energy excitations at various symmetry points within the Brillouin zone, facilitating an understanding of the ultrafast responses of the UV bands and the underlying mechanisms governing them. Our investigation reveals that the photoinduced spectral features remarkably resemble those generated by pure lattice heating, and we disentangle the relative thermal and electronic contributions and their evolutions at different delay times using combinations of decay-associated spectra and temperature-induced differential absorption. The results demonstrate that the photoinduced transients possess a significant thermal origin and cannot be attributed solely to electronic effects. Following photoexcitation, as carriers (electrons and holes) transfer their energy to the lattice, the thermal contribution increases from ∼15% at 1 ps to ∼55% at 500 ps and subsequently decreases to ∼35−50% at 1 ns. These findings elucidate the intricate energy exchange between charge carriers and the lattice in photoexcited perovskite materials and provide insights into the limited utilization efficiency of photogenerated charge carriers.

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“…We note that in a recent paper, the faster carrier cooling processes under longer wavelength excitation have been considered as another cause of the lower threshold. [ 32 ] We also measured the lasing behaviors under CW pumping of different lasting times. As can be seen in Figure S12 (Supporting Information), with temperature increasing (caused by increasing the lasting time), the intensity ratio of stimulated emission to spontaneous emission gradually decreases and the lasing threshold gradually increases, confirming that heat‐induced optical loss is the dominant cause of the lasing suppression.…”

Section: Resultsmentioning

confidence: 99%

Continuous‐Wave Lasing in Perovskite LEDs with an Integrated Distributed Feedback Resonator

Wen

Cao

et al. 2023

Advanced Materials

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Realization of electrically pumped laser diodes based on solution‐processed semiconductors is a long‐standing challenge. Metal halide perovskites have shown great potential toward this goal due to the excellent optoelectronic properties. Continuous‐wave (CW) optically pumped lasing in a real electroluminescent device represents a key step to the current injection laser diode, but it has not been realized yet. This is mainly due to the challenge of incorporating a resonant cavity into an efficient light‐emitting diode (LED) which can sustain intensive carrier injection. Here we report CW lasing in an efficient perovskite LED with an integrated distributed feedback resonator, which shows a low lasing threshold of 220 W·cm−2 at 110 K. Importantly, the LED works well at a current density of 330 A·cm−2, indicating the carrier injection rate already exceeds the threshold of optically‐pumping. Our results suggest that electrically pumped perovskite laser diodes can be achieved once the Joule heating issue is overcome.This article is protected by copyright. All rights reserved

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From optical pumping to electrical pumping: the threshold overestimation in metal halide perovskites

Abstract: The threshold carrier density, conventionally evaluated from optical pumping, is a key reference parameter towards electrically pumped lasers, with the widely acknowledged assumption that optically excited charge carriers relax to...

Cited by 11 publications

References 38 publications

Phonon-driven transient bandgap renormalization in perovskite single crystals

Phonon-driven transient bandgap renormalization in perovskite single crystals

Disentangling Thermal from Electronic Contributions in the Spectral Response of Photoexcited Perovskite Materials

Continuous‐Wave Lasing in Perovskite LEDs with an Integrated Distributed Feedback Resonator

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