Conjugated Polyelectrolytes as Efficient Hole Transport Layers in Perovskite Light-Emitting Diodes.


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Article
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Authors
Lee, Bo Ram 
Yu, Jae Choul 
Park, Jong Hyun 
Lee, Seungjin 
Mai, Cheng-Kang 
Abstract

Perovskite-based optoelectronic devices have been rapidly developing in the past 5 years. Since the first report, the external quantum efficiency (EQE) of perovskite light-emitting diodes (PeLEDs) has increased rapidly through the control of morphology and structure from 0.1% to more than 11%. Here, we report the use of various conjugated polyelectrolytes (CPEs) as the hole injection layer in PeLEDs. In particular, we find that poly[2,6-(4,4-bis-potassium butanylsulfonate)-4 H-cyclopenta-[2,1- b;3,4- b']-dithiophene)] (PCPDT-K) transfers holes effectively, blocks electron transport from the perovskite to the underlying ITO layer, and reduces luminescence quenching at the perovskite/PCPDT-K interface. Our optimized PeLEDs with PCPDT-K show enhanced EQE by a factor of approximately 4 compared to control PeLEDs with PEDOT:PSS, reaching EQE values of 5.66%, and exhibit improved device stability.

Description
Keywords
LEDs, PEDOT:PSS, conjugated polyelectrolytes (CPEs), electroluminescence, hole transport layer (HTL), lead halide perovskites, perovskite light-emitting diodes (PeLEDs)
Journal Title
ACS Nano
Conference Name
Journal ISSN
1936-0851
1936-086X
Volume Title
Publisher
American Chemical Society
Sponsorship
European Commission (622630)
Engineering and Physical Sciences Research Council (EP/M005143/1)
B.R.L., D.D.N., and R.H.F. acknowledge financial support from the Engineering and Physical Sciences Research Council of the UK (EPSRC). B.R.L. was supported by the National Research Foundation of Korea (NRF-2018R1C1B6005778) and the Pukyong National University Research Fund (CD20171504). M.H.S. was supported by the Mid-Career Researcher Program (2018R1A2B2006198), a brand project (1.180061.01) of the Ulsan National Institute of Science and Technology (UNIST), and the KIST-UNIST partnership program (1.150091.01/ 2.150464.01). H.C. was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20173010013200). S.D.S. acknowledges funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme (FP7/2007-2013) under REA grant agreement number PIOF-GA-2013-622630.