Giant Photoluminescence Enhancement in CsPbCl3 Perovskite Nanocrystals by Simultaneous Dual-Surface Passivation
Ghada Ahmed a, Jehad K. El-Demellawi, a, Jun Yin a, Jun Pan a, Osman M. Bakr a, Husam N. Alshareef a, Omar F. Mohammed a
a King Abdullah University of Science and Technology (KAUST) - Saudi Arabia, 4700 King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
Proceedings of International Conference on Perovskite and Organic Photovoltaics and Optoelectronics (IPEROP19)
Kyōto-shi, Japan, 2019 January 27th - 29th
Organizers: Hideo Ohkita, Atsushi Wakamiya and Mohammad Nazeeruddin
Poster, Ghada Ahmed, 095
Publication date: 23rd October 2018

The presence of localized trap states on the surface of CsPbCl3 perovskite nanocrystals (NCs) is one of the greatest challenges precluding the development of optoelectronic applications of these NCs. Passivation of these defect sites provides a promising pathway to remediating their electronic and optical properties, such as the photoluminescence quantum yield (PLQY). Herein, we demonstrate a post-synthetic dual-surface treatment using trivalent metal ion salts, i.e., YCl3, as a new passivation approach that enhances the PLQY up to 60% while preserving the NC size and crystal structure. Such remarkable enhancement of the PLQY along with prolongation of the average PL lifetimes of treated NCs samples indicates effective passivation of the surface defects and subsequent suppression of the formation of surface nonradiative recombination centers. As a segue toward optoelectronic applications, we probed the photoelectric performance of the NCs using ultra-flexible devices; we found that YCl3-treated CsPbCl3 NC films exhibit an order of magnitude larger photocurrent compared to their nontreated counterparts. Our experimental and theoretical results provide an insightful understanding of the effective passivating roles of Y3+ and Cl ions on the surface of CsPbCl3 NCs, as well as offering a new path to synthesize high-quality NCs for UV light conversion applications.

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