Advances in metal halide perovskite lasers: synthetic strategies, morphology control, and lasing emission

.In the past decade,lead halide perovskites have emerged as potential optoelectronic materials in the fields of light-emitting diode,solar cell,photodetector,and laser,due to their low-cost synthesis method,tunable bandgap,high quantum yield,large absorption,gain coefficient,and low trap-state densities.In this review,we present a comprehensive discussion of lead halide perovskite applications,with an emphasis on recent advances in synthetic strategies,morphology control,and lasing performance.In particular,the synthetic strategies of solution and vapor progress and the morphology control of perovskite nanocrystals are reviewed.Furthermore,we systematically discuss the latest development of perovskite laser with various fundamental performances,which are highly dependent on the dimension and size of nanocrystals.Finally,considering current challenges and perspectives on the development of lead halide perovskite nanocrystals,we provide an outlook on achieving high-quality lead perovskite lasers and expanding their practical applications.

Surface ligand modified cesium lead bromide/silica sphere composites for low-threshold upconversion lasing

In recent years,all-inorganic halide perovskite quantum dots(QDs)have drawn attention as promising candidates for photodetectors,light-emitting diodes,and lasing applications.However,the sensitivity and instability of perovskite to moisture and heat seriously restrict their practical application to optoelectronic devices.Recently,a facile ligand-engineering strategy to suppress aggregation by replacing traditional long ligands oleylamine(OAm)during the hot injection process has been reported.Here,we further explore its thermal stability and the evolution of photoluminescence quantum yield(PLQY)under ambient environment.The modified CsPbBr_(3)QDs film can maintain 33%of initial PL intensity,but only 17%is retained in the case of unmodified QDs after 10 h continuous heating.Further,the obtained QDs with higher initial PLQY(91.8%)can maintain PLQY to 39.9%after being continuously exposed in air for 100 days,while the PLQY of original QDs is reduced to 5.5%.Furthermore,after adhering CsPbBr3 QDs on the surface of a micro SiO_(2)sphere,we successfully achieve the highly-efficient upconversion random laser.In comparison with the unmodified CsPbBr_(3)QDs,the laser from the modified CsPbBr_(3)QDs presents a decreased threshold of 79.81μJ/cm^(2)and higher quality factor(Q)of 1312.This work may not only provide a facile strategy to synthesize CsPbBr_(3) QDs with excellent photochemical properties but also a bright prospect for high-performance random lasers.

Arbitrary manipulations of focused higher-order Poincare beams by a Fresnel zone metasurface with alternate binary geometric and propagation phases

The manipulation of high-quality vector beams(VBs)with metasurfaces is an important topic and has potential for classical and quantum applications.In this paper,we propose a Fresnel zone(FZ)metasurface with metallic nanoslits arranged on FZs,which sets alternate binary geometric and propagation phases to cancel the incident spin component and focus the converted spin component(CSC).The rotation designs of nanoslits transform the incident polarization state on the conventional Poincare sphere to VBs on the higher-order Poincare(HOP)sphere.The two orbital angular momentum states of the CSCs were manipulated,and the focused HOP beams were generated.The experimental results demonstrate the broadband generation of arbitrarily focused HOP beams of high quality under the illumination of the red(632.8 nm),green(532 nm),and blue(473 nm)light.This work will be of significance for the applications of VBs in different areas,such as precision metrology,optical micromanipulation,and quantum information.