Deuteration promotes circularly polarized light emission by suppression of vibration

Circularly polarized light (CPL) is critical for advancing photonic technologies such as spin-based optical communication, quantum computing and displays. Developing these technologies necessitates CPL emitters with large dissymmetry factor (g) and high quantum yield (Φ). However, there is an inherent trade-off between these two parameters. Here we integrate molecular deuteration into chiral thermally activated delayed fluorescence (TADF) emitters, leading to marked improvements in both g and Φ. Circularly polarized organic light-emitting diodes incorporating deuterated chiral TADF molecules as either emitters or host exhibit high performance, achieving maximum external quantum efficiency close to 40% and demonstrating up to over twofold enhanced electroluminescence g compared to hydrogenated counterparts. Such advancements are attributed to suppression of vibrations by deuteration. Our deuteration strategy sets a foundation for designing organic chiral emitters with large g and high Φ, paving the way for high-performance CPL in display technologies.