Low-temperature thermal cross-linkable materials with benzocyclobutene groups for solution process of OLEDs

Three novel cross-linkable hole injection materials were designed and synthesized herein. Effective cross-linking was observed for small molecules that incorporate the benzocyclobutene groups at a low temperature of 130 °C or less. These compounds exhibited good solubility in common organic solvents and excellent solvent resistance after cross-linking at a low temperature of 130 °C. The OLED was successfully fabricated using a mixture prepared by adding 4-Isopropyl-4'-methyldiphenyliodonium Tetrakis(pentafluorophenyl)borate (TPFB) to the newly synthesized cross-linkable material as HIL. Maximum current and power efficiencies are 52.92 cd/A and 19.67 lm/W, respectively. The study is expected to accelerate the development of low-temperature cross-linkable materials for solution-processed OLEDs.