Harnessing Hot Phonon Bottleneck in Metal Halide Perovskite Nanocrystals via Interfacial Electron–Phonon Coupling

Abstract

Slow hot carrier (HC) cooling resulting from hot phonon bottleneck has been widely demonstrated in metal halide perovskites. Although manipulating HC kinetics in these materials is of both fundamental and technological importance, this task remains a daunting challenge. Here, via interfacial engineering, i.e., epitaxial growth of Cs 4 PbBr 6 on CsPbBr 3 nanocrystals (NCs), we have revealed an obvious shortening of HC cooling times, evidenced by transient absorption and ultrafast PL spectra. Collaborated with the longitudinal optical (LO) phonon model, theoretical calculations verify the breaking of the hot phonon bottleneck in CsPbBr 3 @Cs 4 PbBr 6 and identify the interfacial electron-LO phonon coupling as the leading mechanism for the observed large tuning of HC cooling times. Especially, the participation of LO phonons from Cs 4 PbBr 6 enables the efficient Klemens channel for hot phonon decay. Our findings establish an effective method to tailor HC dynamics in perovskite NCs, which could be conducive to improving the performance of optoelectronic applications.

Quasiadiabatic electron transport in room temperature nanoelectronic devices induced by hot-phonon bottleneck

“…The dramatic suppression of the energy loss across this ultralong distance is attributed to overpopulated hot longitudinal-optical (LO) phonons that induce frequent LO-phonon reabsorption and thereby remarkably slow down the electron cooling. This hotphonon-assisted electron transport is reminiscent of the previously reported "hot-phonon bottleneck effect" for photoexcited transient carriers (e.g., in perovskites) [24][25][26][27][28][29] . Noting that the hot-phonon bottleneck effect is exempted from any restriction of device operating temperatures, our observations may find promising applications in on-chip energy management for solid-state electronics and energy-harvesting technologies.…”

“…There have been few reports, however, probably because of the lack of measurements so far. Aside from the electron transport, hot-phonon bottleneck effect has been extensively studied for the photoexcited transient state of III-V ionic crystals 24,25 and perovskite compounds [26][27][28][29] , where the energy loss of photocarriers is found to significantly slow down at high excitation levels. In hot-electron transport phenomena, hot-phonon generation was reported experimentally in standard/exotic semiconductors 38,39,[40][41][42] , but its effect on the hot-electron kinetics has been left unclear.…”

Halide Perovskite Lateral Heterostructures for Energy Routing Based Photonic Applications

“…Recently, the inorganic lead halide perovskites (ILHPs) have been emerging as the promising active semiconductors thanks to the cost‐effective fabrication, defect tolerant nature, and superior optical gain properties, which hold great promise to developing novel and functional light‐emitters and lasers. [ 9–15 ] Impressive progress has been made to achieve high‐performance incoherent and coherent light sources in the past few years based on inorganic halide perovskites nanorods, nanowires, microdisks, and nanoplates. [ 11,16–18 ] However, most of these demonstrations are made from the single‐phase ILHPs.…”

In‐Situ and Reversible Enhancement of Photoluminescence from CsPbBr3 Nanoplatelets by Electrical Bias

“…[ 13 ] As a result of the unique ion transport behavior, several unusual physical phenomena have been observed in IHP‐based devices, such as the light‐induced phase segregation and current–voltage hysteresis in solar cells and LEDs. [ 14–17 ] Upon applying electrical bias, the ions will migrate and redistribute in the crystal, which would inevitably impact the photophysical properties of IHPs. Such consequence may be employed as an enabling route for manipulating light emission and designing novel functional devices.…”