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All‐Solution‐Processed Pure Formamidinium‐Based Perovskite Light‐Emitting Diodes
Author(s) -
Wang Juanhong,
Song Chen,
He Zhiwei,
Mai Chaohuang,
Xie Gancheng,
Mu Lan,
Cun Yangke,
Li Jiali,
Wang Jian,
Peng Junbiao,
Cao Yong
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201804137
Subject(s) - formamidinium , materials science , perovskite (structure) , optoelectronics , diode , light emitting diode , chemical engineering , engineering
All‐solution‐processed pure formamidinium‐based perovskite light‐emitting diodes (PeLEDs) with record performance are successfully realized. It is found that the FAPbBr 3 device is hole dominant. To achieve charge carrier balance, on the anode side, PEDOT:PSS 8000 is employed as the hole injection layer, replacing PEDOT:PSS 4083 to suppress the hole current. On the cathode side, the solution‐processed ZnO nanoparticle (NP) is used as the electron injection layer in regular PeLEDs to improve the electron current. With the smallest ZnO NPs (2.9 nm) as electron injection layer (EIL), the solution‐processed PeLED exhibits a highest forward viewing power efficiency of 22.3 lm W −1 , a peak current efficiency of 21.3 cd A −1 , and an external quantum efficiency of 4.66%. The maximum brightness reaches a record 1.09 × 10 5 cd m −2 . A record lifetime T 50 of 436 s is achieved at the initial brightness of 10 000 cd m −2 . Not only do PEDOT:PSS 8000 HIL and ZnO NPs EIL modulate the injected charge carriers to reach charge balance, but also they prevent the exciton quenching at the interface between the charge injection layer and the light emission layer. The subbandgap turn‐on voltage is attributed to Auger‐assisted energy up‐conversion process.