Thermally Cross-Linkable Blended Hole Transport Layer for Solution-Processed Quantum Dot Light-Emitting Diodes

Solution-processed quantum-dot light-emitting diodes (QLEDs) are promising for next-generation display technology. However, the solution process challenges multilayer fabrication due to solvent-induced damage to underlying layers. We propose a robust and highly efficient hole transport layer (HTL) based on a cross-linked blend of N4,N4′-Di(naphthalen-1-yl)-N4,N4′-bis(4-vinylphenyl) biphenyl-4,4′-Diamin (VNPB) and poly[bis(4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA). A precise control of the blend ratio allows a cross-linked structure with solvent resistance and tunable hole mobility and energy levels. The blended HTL, optimized at a 2:1 VNPB/PTAA ratio, outperforms nonblended VNPB or PTAA HTLs in QLEDs. This cross-linked blending strategy offers a promising approach for high-performance QLEDs by addressing electrical properties and solvent issues.