- Solution-processed thermally stable amorphous films of small molecular hole injection/transport bi-functional materials and their application in high efficiency OLEDs
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A series of novel triphenylamine-based small molecular hole transport materials (HTMs) are reported for solution processed organic light-emitting devices (OLEDs). The character of this series of HTMs, denoted as TPD(BTPA)n (n = 1, 2, 4), is connecting the flexible moieties of butadiene bridged triphenylamine (BTPA) to N,N,N′,N′-tetraphenyl-[1,1′-biphenyl]-4,4′-diamine (TPD). The glass transition temperature and crystallization temperature (Tg and Tc) showed a proportional relationship with the number of BTPA moieties. The Tg value of TPD(BTPA)4 can be up to 125.5 °C, which is higher than most of the reported small molecular HTMs (Tg: 54-116 °C). The TPD(BTPA)4 spincoated film showed an outstanding thermal stability which remained amorphous even when annealed at 110 °C, for 48 h. This indicated that the breaking of the planar molecular structure with BTPA moieties can suppress intermolecular stacking. The solution processed OLEDs with 8-hydroxyquinoline aluminum (Alq3) as emission and electron transport layers showed high stability at high operation current (>400 mA cm-2). The OLED with TPD(BTPA)4 achieved a maximum current efficiency of 5.83 cd A-1 (at the operation current density > 400 mA cm-2), which is higher than the maximum current efficiency of most evaporation and solution processed OLEDs in identical structures.
- Zhao, Xiaoming,Wang, Shirong,You, Jing,Zhang, Yuteng,Li, Xianggao
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- Novel hole transporting materials with a linear π-conjugated structure for highly efficient perovskite solar cells
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Novel small-molecule hole transporting materials (HTMs) with a linear π-conjugated structure have been synthesized. The perovskite solar cell based on 2TPA-2-DP as the HTM exhibits an encouraging power conversion efficiency of 9.1% under AM 1.5 G (100 mW cm-2) illumination, which is the first demonstration of an effective perovskite solar cell using a linear structured HTM. This journal is the Partner Organisations 2014.
- Wang, Junjie,Wang, Shirong,Li, Xianggao,Zhu, Lifeng,Meng, Qingbo,Xiao, Yin,Li, Dongmei
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p. 5829 - 5832
(2014/05/20)
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- Synthesis and properties of novel hole-transporting materials with triphenylamine units
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Two novel organic hole-transporting materials have been synthesized by combination of triphenylamines (TPA) via π-conjugated bonds using Wittig reaction. The structures were characterized by NMR, FT-IR and HRMS. The optical, electrochemical and thermal properties of the materials were studied in detail. The results show that these two compounds have blue emission, proper HOMO levels and high thermal stability. Furthermore, a quantum chemical calculation on electron distribution of the two compounds was performed, which suggests the current synthesized materials would be promising candidates for hole-transporting materials.
- Gao, Wen Zheng,Li, Xiang Gao,Wang, Shi Rong,Lv, Hai Jun
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p. 141 - 144
(2012/06/29)
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