Break of thermal equilibrium between optical and acoustic phonon branches of CsPbI3 under continuous-wave light excitation and cryogenic temperature

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外文摘要：The kinetic of low-temperature carrier and lattice of lead-halide perovskite is yet to be fully understood.In this work,we investigate the steady-state photoluminescences(PLs)of CsPbI3 at the environmental temperature(Te)ranging from 20 K to 300 K,and observed anomalous behaviors at cryogenic tempera-tures:The carrier temperature(Tc)of pure CsPbI3 exhibits a negative correlation with Te,accompanied by an expansion in Urbach tails of absorption spectra(Abs.)and excessive red-shifts at peak energy of PLs.These phenomena are also observed in those samples containing a certain amount of Cs4PbI6,but to a lesser extent and occurs at lower temperatures.It is attributed to the intensified hot phonon bottleneck effect(HPB)in CsPbI3 at cryogenic Te,which hinders the energy transfer from hot carriers,via longi-tudinal optics(LO)phonons to longitudinal acoustic(LA)phonons,to the ambient.For samples under continuous-wave laser excitation,in specific,the barrier induced by the enhanced HPB at low Te pre-vents the effective thermalization among carriers,LO and LA phonons,which,therefore,form thermally isolated ensembles with different temperatures.At cryogenic Te range,the elevated temperatures of car-rier and LO phonon expand the high-energy side of PLs and the low-energy tail of Abs.,respectively.For those samples in which the CsPbI3 is mixed with Cs4PbI6,the interfacial LO-LO interaction across them provides a bypass for heat dissipation,mitigating the heat accumulation in LO-phonons of CsPbI3.The results suggest that a strong HPB effect may break the thermal equilibrium among different branches of phonons in the lattice under certain extreme conditions.

外文关键词：

CsPbI3Cs4PbI6Low-temperature carrierLattice kineticHot phonon bottleneck effectInterfacial LO-LO interaction

作者：

Rongliang Deng、Yihang Chen、Xiaotong Fan、Guolong Chen、Shuli Wang、Changzhi Yu、Xiao Yang、Tingzhu Wu、Zhong Chen、Yue Lin

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作者单位：

Department of Electronic Science,Fujian Engineering Research Center for Solid-State Lighting,Xiamen University,Xiamen 361005,China

Institute of Electromagnetics and Acoustics,School of Electronic Science and Engineering,Xiamen University,Xiamen 361005,China

Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM),Xiamen 361102,China

基金：

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaExternal Cooperation Program of FujianFundamental Research Funds for the Central UniversitiesFundamental Research Funds for the Central UniversitiesMajor Science and Technology Project of Xiamen in China

项目编号：

6237414212175189119043022022I000420720190005207202200853502Z20191015

出版年：

2024

DOI：

10.1016/j.cclet.2023.109346

中国化学快报(英文版)

中国化学会

中国化学快报(英文版)

CSTPCD

影响因子：0.771

ISSN：1001-8417

年,卷(期)：2024.35(7)