Highly efficient organic light emitting diodes fabricated by solution process with new hole transport materials cross-linked at 120 °C

•Low cross-linking temperature (120 °C) and excellent mobility (1.01 × 10−2 cm2V−1s−1).•Outstanding efficiency of 130.5 cdA−1 (37.3% EQE) for solution-processed OLED.•Interface mixing zone estimated to be 3.8 nm.•Preferred horizontal orientation of transition dipole moment for spin-coated films.