Optical Lasing From Organic Host-guest Microcrystals And All-inorganic Perovskite Films

Lasers have unique properties,including high intensity,directionality,monochromatic emission and large coherence length.Relevant applications have spread to many areas,e.g.photoelectric,communications,medicine.In this study,we focused on two different materials:host-guest microcrystals with an organic dye as gain material and all-inorganic perovskite films,demonstrating their lasing properties.This provides a further insight of photophysical and photochemical processes and a route to developing optoelectronic devices.The main content was composed of two parts:1.We prepared a novel host-guest complex single crystal material based on pillar[5]arene(P5)and an organic laser dye trans-4-[p-(dimethylamino)styryl]-1-methylpyridinium iodide(DASP)through self-assembly processes.Single crystal structure characterization showed that two P5 molecules act as a supramolecular nanocapsule for one isolated DASP molecule,forming 2P5(?)DASP structure.The dye DASP molecules were uniformly oriented in the host-guest single crystals.This spatial confinement effectively restricted aggregation-caused quenching(ACQ)effects and other nonradiative channels,leading to high luminescent efficiency compared to the isolated DASP.Together with its regular shape and smooth surface,each 2P5]DASP microcrystal formed a Fabry-Pdrot(F-P)microcavity and produced a stable laser output with a low threshold(?230 ?J/cm2)and a high Q factor(?1300).2.We reported a facile one-step solution-based approach to grow all-inorganic CsPbX3(X=Br,I)perovskite films with pinhole-free and ultra-smooth surface,by incorporating long-chain octylammonium halide(OAX)as additive.The optimal CsPbBr3 perovskite films produced amplified spontaneous emission(ASE)with low threshold of 14 uj/cm2 and high gain coefficient of 380 cm-1,superior to other CsPbBr3 colloidal nanostructures and films.We also demonstrated that this strategy could be extended to CsPbBrxI3-x films,and the ASE wavelength could be readily tuned between 535 and 715 nm.These merits lead to a vertical cavity lasing with ultralow threshold of 187 nJ/cm2.Furthermore,CsPbX3 films have even been kept in atmosphere without encapsulation for months.