Excitation-Power Dependence of Free Exciton Photoluminescence of Semiconductors

Shibata, Hajime; Sakai, Masamichi; Yamada, A.; Matsubara, Koji; Sakurai, Katsutoshi; Tampo, Hitoshi; Ishizuka, Shogo; Kim, Kyoung-Kook; Niki, Shigeru

doi:10.1143/jjap.44.6113

Cited by 52 publications

(54 citation statements)

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“…Fast charge trapping process that was widely observed within the perovskite can also influence this linear relationship. [ 22,31,35,40,41 ] In addition, when multiple charge recombination processes (e.g., first‐order radiative and non‐radiative, and second‐order radiative) exist within the perovskite, it is usually hard to observe a simple linear or quadratic relationship between the I PL and I exc (Figure S5, Supporting Information). As such, it is hard in using the relationship between the I PL and the I exc to determine the perovskite charge character in experiment especially when large excitation fluence is used.…”

Section: Resultsmentioning

confidence: 99%

Exciton Character and High‐Performance Stimulated Emission of Hybrid Lead Bromide Perovskite Polycrystalline Film

Shi

et al. 2020

Advanced Optical Materials

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optical communication, detecting, and photovoltaic applications, owing to their advantages of tunable bandgap, long car rier lifetime, and high light absorption. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] These advantages have arisen because of the distinctive semiconductor and photo physics properties that such materials possess, including ultrahigh bandedge density of states, [15] ultralow charge trap ping crosssection, [16] and low defect den sities. [17] Recent findings, including the ultraslow hot carrier cooling, [18,19] ultralong polarization memory, [20] giant spinorbit Rashba splitting, [21] and weak electronlattice coupling, [22] further increase mys tery of the perovskites. Underlying these alluring characteristics are intrinsic elec tronic states of the perovskite materials, while the electronic structure ultimately determines their photoelectric conversion mechanisms and performances. [23,24] As such, exploring electronic states of the hybrid perovskite pos sesses important implications for improving performance of current devices and expanding application horizons of these materials.Nonetheless, a clear understanding of the intrinsic elec tronic structure and chargecarrier characters of the perovskite remains lacking, and controversies on these properties have always been ongoing. These endless controversies arise because of the observed complicated photophysics characteristics and distinct scenarios proposed for interpreting them. For instance, the electronic origin for bandedge dual emission bands within both the single crystal and polycrystalline perovskites is one of the controversial focuses. [25][26][27][28][29][30][31][32] These dual emission bands pro vide important spectroscopic information for elucidating the fine structure of bandedge electronic states. Photon recycling provided a satisfied explanation for this phenomenon within the single crystal methylammonium lead bromide (MAPbBr 3 ). [25] Indirect band structure induced by a static or dynamical Rashba effect is another common interpretation [30][31][32] since a giant Rashba splitting within MAPbBr 3 was indeed observed using angular resolved photoelectron spectroscopy. [21] The indirect band structure scenario was also proposed to explain an unu sual temperature dependent secondorder radiative recombina tion velocity. [33] In contrast, an experimental result supporting the direct bandgap structure was observed recently. [34] Another controversial focus is on the charge character of perovskite. The bandedge emission of the bromide perovskite was once Electronic states of hybrid perovskites enable their exceptional optoelectronic applications. Herein, through heterojunction enhanced exciton dissociation and global tracing of multiple radiative electronic states across wide temperature regions, it has been found that excitons while not free carriers dominate the bandedge photoelectric properties of hybrid lead bromide perovskite (MAPbBr 3 ). MAPbBr 3 has exhibited two types of excitons with giant binding energies and superior phas...

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Section: Resultsmentioning

confidence: 99%

Exciton Character and High‐Performance Stimulated Emission of Hybrid Lead Bromide Perovskite Polycrystalline Film

Shi

et al. 2020

Advanced Optical Materials

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“…To further understand the relaxation kinetics of photo-generated charge carriers correlated to defect states of perovskite thin films, excitation-power dependent PL was undertaken and shown in Fig.4. It is worthwhile noting that the PL intensity I PL has a relationship with the power P of the excitation laser as I PL  P β , where β is the power index [21,22].…”

Section: Resultsmentioning

confidence: 99%

Impact of perovskite precursor solution temperature on charge carrier dynamics and photovoltaic performance of perovskite based solar cells

Namkoong

Mamun

Ava

et al. 2017

Organic Electronics

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Even though perovskite based solar cells have been routinely fabricated with preheated perovskite solutions, currently the underlying mechanism of how the perovskite precursor solution temperature influences perovskite solar cells has not been studied yet. Therefore, we investigated the impacts of perovskite solution temperatures on charge carrier dynamics of perovskite film and perovskite solar cell performance that were quantitatively analysed using steady-state photoluminescence (PL), time-resolved emission spectra (TRES), excitation-dependence of PL and current-voltage measurements. It is found that the perovskite solution temperature greatly influenced the morphologies, defect densities and states, and charge recombination dynamics of perovskite thin films. Particularly, steady-state and time-resoled PL measurements revealed that perovskite thin films prepared with the perovskite solution temperature around 70 C produced lowest surface and bulk defect densities. In addition, it is found that the perovskite solution temperature around 70 C led to exciton-like transitions while lower

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“…The black line represents an analysis with a 3 rd order polynomial for the case of the polycrystalline perovskite (a) and with a 2 nd order polynomial in the case of the microcrystals (b) and the nanocrystals (c).To further investigate the recombination mechanism in the MAPbBr3 thin films, the time-integrated PL intensity (at the spectral maximum) was plotted as a function of the excitation density(Figure 4, only data below the threshold of exciton-exciton annihilation and Auger recombination is shown). The result was analyzed with a power law function of the form ~K, where F is the excitation fluence or density, and k is a real number exponent, which provides information about the order of the recombination process 13,66,67.…”

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confidence: 99%

Origin of the Enhanced Photoluminescence Quantum Yield in MAPbBr₃ Perovskite with Reduced Crystal Size

et al. 2018

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Methylammonium lead bromide perovskite (MAPbBr3) has been widely investigated for applications in visible perovskite light-emitting diodes (LEDs). Fine-tuning of the morphology and of the crystal size, from the microscale down to the quantum confinement regime, has been used to increase the photoluminescence quantum yield (PLQY). However, the physical processes underlying the PL emission of this perovskite remain unclear. Here, we elucidate the origin of the PL emission of polycrystalline MAPbBr3 thin films by different spectroscopic techniques. We estimate the exciton binding energy, the reduced exciton effective mass, and the trap density. Moreover, we confirm the coexistence of free carriers and excitons, quantifying their relative population and mutual interaction over a broad range of excitation densities. Finally, the enhanced PLQY upon crystal size reduction to the micro- and nanometer scale in the presence of additives is attributed to favored excitonic recombination together with reduced surface trapping thanks to efficient passivation by the additives.

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Excitation-Power Dependence of Free Exciton Photoluminescence of Semiconductors

Cited by 52 publications

References 1 publication

Exciton Character and High‐Performance Stimulated Emission of Hybrid Lead Bromide Perovskite Polycrystalline Film

Exciton Character and High‐Performance Stimulated Emission of Hybrid Lead Bromide Perovskite Polycrystalline Film

Impact of perovskite precursor solution temperature on charge carrier dynamics and photovoltaic performance of perovskite based solar cells

Origin of the Enhanced Photoluminescence Quantum Yield in MAPbBr₃ Perovskite with Reduced Crystal Size

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Excitation-Power Dependence of Free Exciton Photoluminescence of Semiconductors

Cited by 52 publications

References 1 publication

Exciton Character and High‐Performance Stimulated Emission of Hybrid Lead Bromide Perovskite Polycrystalline Film

Exciton Character and High‐Performance Stimulated Emission of Hybrid Lead Bromide Perovskite Polycrystalline Film

Impact of perovskite precursor solution temperature on charge carrier dynamics and photovoltaic performance of perovskite based solar cells

Origin of the Enhanced Photoluminescence Quantum Yield in MAPbBr3 Perovskite with Reduced Crystal Size

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Origin of the Enhanced Photoluminescence Quantum Yield in MAPbBr₃ Perovskite with Reduced Crystal Size