Terahertz Conductivity within Colloidal CsPbBr3 Perovskite Nanocrystals: Remarkably High Carrier Mobilities and Large Diffusion Lengths

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• 作者：Gurivi Reddy Yettapu ; Debnath Talukdar ; Sohini Sarkar ; Abhishek Swarnkar ; Angshuman Nag ; Prasenjit Ghosh ; Pankaj Mandal
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：August 10, 2016
• 年：2016
• 卷：16
• 期：8
• 页码：4838-4848
• 全文大小：573K
• 年卷期：0
• ISSN：1530-6992

文摘

Colloidal CsPbBr₃ perovskite nanocrystals (NCs) have emerged as an excellent light emitting material in last one year. Using time domain and time-resolved THz spectroscopy and density functional theory based calculations, we establish 3-fold free carrier recombination mechanism, namely, nonradiative Auger, bimolecular electron–hole recombination, and inefficient trap-assisted recombination in 11 nm sized colloidal CsPbBr₃ NCs. Our results confirm a negligible influence of surface defects in trapping charge carriers, which in turn results into desirable intrinsic transport properties, from the perspective of device applications, such as remarkably high carrier mobility (∼4500 cm² V^–1 s^–1), large diffusion length (>9.2 μm), and high luminescence quantum yield (80%). Despite being solution processed and possessing a large surface to volume ratio, this combination of high carrier mobility and diffusion length, along with nearly ideal photoluminescence quantum yield, is unique compared to any other colloidal quantum dot system.