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Efficient Solution‐Processed Inverted Organic Light‐Emitting Diodes by Using Polyethyleneimine as Interface Layer
Author(s) -
Zhou Tao,
Ling Zhitian,
Tang Zhenyu,
Wang Shuanglong,
Guo Kunping,
Chen Guo,
Cheng Zhiqun,
Dai Xiwang,
Gao Haijun,
Xu Tao,
Wei Bin
Publication year - 2018
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201800138
Subject(s) - oled , materials science , diode , layer (electronics) , optoelectronics , deposition (geology) , interface (matter) , photoluminescence , nanotechnology , composite material , contact angle , paleontology , sessile drop technique , sediment , biology
This paper demonstrates the use of multiple polyethyleneimine (PEI) films acting as interface layers in the inverted organic light‐emitting diodes (OLEDs) to solve the mixing problem between different functional layers. The morphological, electrical and photoluminescence characteristics of PEI films are systematically investigated. The thickness of PEI layers is optimized to achieve both good electron transport and ability of preventing the miscibility. The authors’ results show that the insertion of double PEI interface layers in the inverted OLEDs allow the deposition of electron transport layer and emissive layer all in solution. Finally, the authors report an inverted green OLED with one and double PEI interface layers. The green OLED with double PEI interface layers yields a maximum current efficiency of 45.2 cd A −1 , which is close to the device using thermal deposition method. The authors thus believe that the application of multiple PEI interface layers could provide a promising way to obtain highly efficient OLEDs in solution processing.