| Abstract: | White‐color light emitters from single organic molecule without heavy metals are valuable for practical applications in organic light‐emitting devices. In this study, carbazole (Cz)–dibenzofuran (DBF) donor–acceptor dyads are designed for white‐color light emitters. Originally, these molecules show photoluminescence (PL) in near ultraviolet region. However, upon successive ultraviolet (UV) irradiation, white‐color PL appears, comprising dual‐color phosphorescence from the amorphous and crystalline state of the dyad. A continuous UV irradiation makes the twisting angle between the Cz and DBF planes flatten through the triplet‐excited state, which proceeds crystallization. Thermal annealing and UV irradiation can switch the blue‐ and white‐color phosphorescences from the dyad. Furthermore, charge injection generates white‐color electroluminescence. The materials with PL color modulation ability by UV‐light irradiation and heating can be applicable as light‐ and thermo‐sensors. |
