Highly efficient chrysene emitters based on optimized side groups for deep blue emission

Diphenylamine substituted with methyl groups was used as a side group to realize high efficiency chrysene deep blue emitters. Three chrysene derivatives substituted with side groups were successfully synthesized: tetra-o-tolylchrysene-6,12-diamine (o-DPAC), tetra-m-tolylchrysene-6,12-diamine (m-DPAC), and tetra-p-tolyl-chrysene-6,12-diamine (p-DPAC). The maximum PL (Photoluminescence) emission wavelengths of the three materials in solution and in a film were shortest for o-DPAC and longest for p-DPAC. The highly twisted structure of o-DPAC showed the narrowest FWHM (47 nm) in the deep blue region with a PLmax of 449 nm in the film state. The three synthesized materials showed excellent thermal stability with a high Td over 370 °C. EML was applied to a non-doped OLED device considering the band gap of synthesized materials. Among the synthesized materials, the m-DPAC device achieved excellent EL performance of CIE x, y (0.14, 0.09), 4.89 cd/A, 3.60 lm/W, and an EQE of 6.18%.