Star-shaped cross-linkable hole transport materials with high triplet energy and deep HOMO energy enable efficient solution-processed deep-blue TADF OLEDs

• • m-V-CzDPA and m-V-DPADPA exhibit high triplet energies of 2.89 eV and 2.87 eV, respectively, effectively confining triplet excitons in the emitting layer and preventing energy back-transfer, which is critical for maintaining high efficiency in deep-blue TADF OLEDs. • • Carrier diffusion coefficients of 0.54 cm2 s−1 for x-m-CzDPA and 0.44 cm2 s−1 for x-m-DPADPA, with hole mobilities of 4.30×10−4 and 1.39×10−4 cm2 V−1 s−1, demonstrate outstanding intrinsic hole transport capability, enabling balanced charge transport and reduced driving voltage. • • Solution-processed deep-blue TADF-OLEDs employing x-m-CzDPA achieved a maximum current efficiency of 5.25 cd A−1 and maximum external quantum efficiency of 18.06%, with CIE coordinates of (0.162, 0.042), satisfying the BT.2020 standard for ultra-high-definition displays. • • This is the first report of cross-linkable HTMs serving as efficient deep-blue TADF-OLEDs via solution processing, overcoming interlayer mixing and energy level mismatch, and providing a viable route for large-area, flexible deep-blue OLED displays.