Research On Lead Halide Perovskite Micro-nano Laser

Lead halide perovskites have been very promising photovoltaic and light emission materials due to their unique properties,such as high absorption coefficients,long carrier diffusion lengths,wide-band tunable emissions,high quantum yield,and low densities of trap states,etc.In addition,the perovskites have a high optical gain and long range ambipolar charge-transport property,electrically driven lasers may be realized in the next few years.Perovskite micro-nano lasers are expected to bring new opportunities for nano photonics,chemical-biosensing,and optical computing.In this thesis,the preparation technology of lead perovskite halide had been developed and their optical properties were characterized.The main innovations are as follows:1.The large-area perovskites micro disk arrays of Cs Pb X₃(X=Cl,Br)were prepared by a polydimethylsiloxane(PDMS)cylindrical-hole-template confined solution growth method.Uniform rectangle micro disks with a side length of 2-3?m are compactly patterned on a square lattice with a?=20?m on arbitrary substrate.Simultaneously lasing outputs from nine micro disks was realized owing to their similarly low thresholds of 3-12?J/cm².By adjusting the halide substitution in Cs Pb Cl_3-xBr_x,the coherent output wavelengths of micro disk can be well tuned in the blue–green region from 425,460,500 to 540 nm.Furthermore,we demonstrated the integration of deep blue,blue,cyan,and green four-color micro disk laser on the same substrate through selective replacement of Cl by Br from Cs Pb Cl₃micro disks in HBr vapor phase.2.Perovskite nanowire arrays fabricated by PDMS rectangular groove template The template confinement effect led to the directional growth of MAPb X₃(X=Br,I)along groove template into perovskite nanowire.Well defined dimensions and uniform geometries enabled individual perovskite nanowire to function as high-quality cavity lasers with almost identical optical modes and similarly low lasing thresholds,allowing them to ignite simultaneously as a laser array.Optical tests demonstrated that perovskite nanowire laser array exhibited good photo stability with an operation duration exceeding 4?10⁷ laser pulses.3.Quasi-2D perovskite films were prepared by solution spin-coating method.Their structure and optical properties were adjusted by the radio of 2D and 3D perovskite.However,the PLQY of quasi-2D perovskite films increased with the decreased of n,the gain coefficients decreased.A high PLQY?24%was obtained from n=3.5 quasi-2D perovskite films.Amplified spontaneous emission(ASE)from n=11 quasi-2D perovskite films were achieved at a low thresholds?1.4?J/cm²,with gain coefficients?64 cm^-1.4.A method of fabricating concentric rings on quasi-2D perovskite films was proposed.The lower photoresist films melts to form the coffee ring effect,which makes the upper perovskite film forms a concentric ring structure.At the same time,the bridge between concentric rings provides a window for perovskite laser emission.It was demonstrated that concentric rings formed a high Q?1800 optical micro cavity and decreased the thresholds.