Date：2017-08-24 |
Views：2103 |
【Academic writing Sharing 20170823】 |
Highly twisted organic molecules with ortho linkage as the efficient bipolar hosts for sky-blue thermally activated delayed fluorescence emitter in OLEDs
Article excerpt is from: Jingfang Pei, Xiaoyang Du, Chao Li, Chuan Wang, Cong Fan, Haochen Tan, Bei Cao, Fangyi Huang, Silu Tao, Jingze Li
Organic Electronics 50 (2017) 153-160
Two new host materials, CzDPPy and tCzDPPy, were designed and synthesized. Due to the steric hindrance of carbazole at the ortho positions of diphenylpyridine, both CzDPPy and tCzDPPy adapted highly twisted molecular conformation, which could effectively minimize their p conjugation and endow them the high triplet energies of 2.67 and 2.64 eV, respectively. Organic light-emitting devices (OLEDs) were fabricated by using CzDPPy and tCzDPPy as the host materials and 2CzPN as the sky-blue emitter. The peak current efficiency of 34.8 cd/A, power efficiency of 33.1 lm/W and external quantum efficiency of 16.0% were realized for the CzDPPy-based TADF OLED, along with the satisfactory CIE coordinate of (0.18, 0.34) at 100 cd /m2.
