Overcoming the electroluminescence efficiency limitations of perovskite light-emitting diodes

Himchan Cho(Pohang University of Science and Technology), Su-Hun Jeong(Pohang University of Science and Technology), Min Ho Park(Pohang University of Science and Technology), Young‐Hoon Kim(Pohang University of Science and Technology), Christoph Wolf(Pohang University of Science and Technology), Chang‐Lyoul Lee(Gwangju Institute of Science and Technology), Jin Hyuck Heo(Kyung Hee University), Aditya Sadhanala(University of Cambridge), NoSoung Myoung(Gwangju Institute of Science and Technology), Seunghyup Yoo(Korea Advanced Institute of Science and Technology), Sang Hyuk Im(Kyung Hee University), Richard H. Friend(University of Cambridge), Tae‐Woo Lee(Pohang University of Science and Technology)
Science
December 3, 2015
10.1126/science.aad1818
Cited by 2,885Open Access
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Abstract

Organic-inorganic hybrid perovskites are emerging low-cost emitters with very high color purity, but their low luminescent efficiency is a critical drawback. We boosted the current efficiency (CE) of perovskite light-emitting diodes with a simple bilayer structure to 42.9 candela per ampere, similar to the CE of phosphorescent organic light-emitting diodes, with two modifications: We prevented the formation of metallic lead (Pb) atoms that cause strong exciton quenching through a small increase in methylammonium bromide (MABr) molar proportion, and we spatially confined the exciton in uniform MAPbBr3 nanograins (average diameter = 99.7 nanometers) formed by a nanocrystal pinning process and concomitant reduction of exciton diffusion length to 67 nanometers. These changes caused substantial increases in steady-state photoluminescence intensity and efficiency of MAPbBr3 nanograin layers.

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