Dynamic Modulation of Multicolor Laser Emission From Organic Microcrystal

ABSTRACT Development of multicolor organic nano/micro lasers has attracted significant attention due to their applications ranging from sensing, display technology to on‐chip optical communication and computing. Nevertheless, dynamic switch and modulation between multicolor laser outputs remains a formidable task owing to lack of well‐demonstrated mechanism. Here, we demonstrated dynamic modulation of tricolor laser emission based on doped organic microplate crystals, in which the guest of 2% α,ω‐bis(biphenyl‐4‐yl)‐terthiophene (BP3T) uniformly doped in the host 4,4′‐(3‐dibenzothiophene)‐stilbene (4,4′‐(3‐dibenzothiophene)‐stilbene (B3BtS) crystalline matrix. Time‐resolved photoluminescence results reveal an efficient and fast Förster resonance energy transfer (FRET) from B3BtS to BP3T with an efficiency of 86.8% and a rate of 14.5 ns −1 . Indeed, laser emission of doped organic microplate crystals developed at 550 nm from the host of BP3T above a threshold of 3.7 µJ/cm 2 owing to the efficient FRET. However, when continuously increasing the pump energy, laser emissions at 460 and 490 nm from B3BtS gradually emerge at the expense of the BP3T lasing. Therefore, dynamic modulation of tricolor laser emission of doped organic microplate crystals originates from the competitive between the FRET rate from the host to the guest and the stimulated emission rate of host molecules.