Surface Engineering of Silicon Quantum Dots: Does the Ligand Length Impact the Optoelectronic Properties of Light‐Emitting Diodes?

Herein, silicon quantum dot light-emitting diodes (SiQD LEDs) are investigated to explore the interplay between their electroluminescence (EL) blue shift and SiQD ligand length on surface. The is essential for LED fabrication ensure colloidal stability, but it also hinders efficient charge transport inside LED. Consequently, SiQDs functionalized via organolithium reagents with hexyl, octyl, dodecyl obtain a low-SiQD surface coverage therefore improved transport. With increasing length, potential barrier increases, which ideal carrier confinement, trade-off has be found. A sweet spot performance found octyl-functionalized highest irradiance (734 μW cm−2) external efficiency (1.48%), compared shorter hexyl- longer dodecyl-capped SiQDs. exhibit size distribution, whereas bandgap energy of inversely proportional size. Therefore, large short accessible at low voltages, small long ligands require elevated voltages. This leads broadening EL spectrum length-controlled size-selective activation.