Design Rules and Experimental Validation of Carbene–Metal–Amide Luminophores: Systematic Modification of the Amide Ligand

Abstract

Carbene–metal–amides (CMAs) have emerged as promising thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs). Here, we present a comprehensive computational investigation of amide ligand effects on CMA photophysics, examining ca. 70 complexes through density functional theory and its time-dependent extension. Our systematic analysis reveals how structural modifications influence key parameters, including HOMO–LUMO overlap, singlet–triplet energy gaps, oscillator strengths, and metal–ligand bond energies. We demonstrate emission tunability across the visible spectrum through strategic modification of carbazole, indole, carboline, and guanidine-based amides. The computational screening identified promising candidates balancing TADF efficiency with molecular stability. Guided by these predictions, we synthesized two rationally designed complexes with contrasting excited state alignments, and tested their photo- and radioluminescence performance. This combined theoretical–experiment approach establishes clear structure–property relationships for CMA design and demonstrates the effectiveness of computational screening in accelerating OLED material development.