Exploiting Two-Step Processed Mixed 2D/3D Perovskites for Bright Green Light Emitting Diodes

© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Mixed 2D/3D perovskite films with self-assembled quantum wells have significantly improved the performance of perovskite light emitting diodes (PeLEDs). In this work, such films are fabricated through a two-step interdiffusion method that is widely employed in processing of perovskite solar cells, however, remains rarely explored for PeLEDs. The effects of incorporating large-cation ligand, i.e., butylammonium bromide (BABr) into formamidinium lead bromide (FAPbBr 3 ) based perovskites, in terms of film composition, morphology, optoelectronic properties as well as device performance are thoroughly investigated in this method. By modulating BABr:PbBr 2 ratio in the precursor solution, the optimal device shows a maximum external quantum efficiency (EQE) of 7.36% at 147.7 mA cm −2 and a brightness of 37 720 Cd m −2 at 5 V. The performance is remarkably higher than a reference device without BABr that shows a maximum EQE of 2.53% and a brightness of 6190 Cd m −2 at 5 V. The versatility of this method is further extended to another large-cation ligand, 4-fluoro-benzylammonium bromide (F-BZABr), which leads to maximum EQE of 8.55%. This work indicates two-step processed mixed 2D/3D perovskites are promising for bright green PeLEDs.

Publication year:2019

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BOF-publication weight:10

CSS-citation score:4

Authors:International

Authors from:Government, Higher Education

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