Against the Wallach's Rule Through Rational Design of Metal‐Free Chiral Perovskites Toward Efficient Red Circularly Polarized Phosphorescence

The potential applications of circularly polarized phosphorescent materials in chiroptical devices have attracted considerable interest. Nevertheless, the design of efficient near-infrared/red circularly polarized phosphorescent pure organic materials remains a significant challenge, largely due to the limitations imposed by the energy-gap law and Wallach's rule. In this study, the chiral metal-free perovskite strategy is employed to overcome these restrictions. The introduction of cyclohexylenediammonium cations as the A-site of chiral metal-free perovskites results in the generation of an efficient near-infrared/red phosphorescence at 637 nm with a lifetime of up to 227.98 µs. Furthermore, the photoluminescence quantum yield (PLQY) can reach up to 71.22%, accompanied by an anisotropy factor of 9.8 × 10-3. The figure of merit (FM = PLQY× |glum|) is 6.98 × 10-3, which is the highest value achieved among all the pure organic circularly polarized phosphorescent materials. The work proposes a unique strategy to achieve highly efficient near-infrared/red circularly polarized phosphorescence based on non-conjugated luminophores, which is accomplished by combining the superior optical and electronic properties of metal-free perovskites with chirality based on the rational molecular design.