Lowering the driving voltage and improving the luminance of blue fluorescent organic light-emitting devices by thermal annealing a hole injection layer of pentacene
Gao Jian1, 2, 3, Yu Qian-Qian1, 2, 3, Zhang Juan1, 2, 3, Liu Yang1, 2, 3, Jia Ruo-Fei1, 2, 3, Han Jun1, 2, 3, Wu Xiao-Ming1, 2, 3, †, Hua Yu-Lin1, 2, 3, ‡, Yin Shou-Gen1, 2, 3, §
       

(color online) XRD patterns of the pentacene films on sapphire substrate before and after annealing (100 °C, 120 °C, and 150 °C). The thickness of the pentacene film is 50 nm.