Research On The Lasing Properties Of CsPbBr₃ Inorganic Perovskite Materials And Devices

Lasers,as a key component of integrated photonic devices,have potential applications in data communication devices,medical diagnosis,sensors and spectral tools.Compared with organic semiconductor materials,inorganic perovskite materials have become one of the most promising optical gain materials in the laser field due to their peculiar optoelectronic properties such as tunable band gap,high carrier mobility and low auger recombination.It is expected to realize low-threshold lasers and promote the development of electrically pumped lasers.Therefore,this thesis is based on the lasing properties of inorganic CsPbBr3 materials and devices.The details are as follows:(1)We designed a novel perovskite plasmonic nanolaser based on a semiconductor-graphene-insulator-metal(SGIM)structure in the visible region,and the graphene is placed between an inorganic CsPbBr3 nanowire and a semicircular silver ridge substrate deposited with silicon dioxide(SiO2).Based on the finite element method,the influences of the graphene thickness and CsPbBr3 nanowire radius on the mode characteristics and transmission characteristics of the hybrid plasmonic waveguide were investigated.We obtained the optimal structure parameter of the hybrid plasmonic waveguide,which could achieve a low gain threshold of 0.72 μm-1 in the visible region.Meanwhile,we investigated the spatial distribution of the surface plasmon polariton mode and the perovskite guided mode.Compared to a gold or copper bridge substrate,the plasmonic waveguide based on the sliver bridge substrate exhibited a stronger emission intensity,smaller propagation loss and larger propagation distance,leading to a lower gain threshold.(2)We adopted a facile and low-cost synthesis scheme to prepare the CsPbBr3 quantum dots(QDs)modified by lead bromide(PbBr2)and tetraoctylammonium bromide(TOAB)ligands at room temperature in open air.The prepared CsPbBr3 QDs exhibited a photoluminescence quantum yield(PLQY)of 96.6%and a low amplified spontaneous emission(ASE)threshold of 12.6 μJ/cm2,which is attributed to the stronger combination of the modified ligand and the quantum dots.Stable ASE intensity was realized from the CsPbBr3 QDs doped with PMMA,and the lasing intensity remained at 97%of the initial value after aging for one week.Meanwhile,the enhanced ASE properties of the CsPbBr3 QDs-doped PMMA based on distributed feedback(DFB)substrate was achieved with a lower threshold of 3.6 μJ/cm2,which is 28.6%of that of the(PbBr2+TOAB)-treated CsPbBr3 QDs without PMMA.(3)We investigated a novel magnetically controllable random lasers with tunable random laser properties.The Fe3O4@Ag nanoparticles(NPs)with both magnetic and plasmonic properties were introduced into a liquid gain medium environment with a random laser pumping threshold of 7.2 μJ/cm2,which is 66.1%of the pure gain dielectric solution threshold.The particle motion of Fe3O4@Ag NPs was further controlled by an external magnetic field to effectively modulate the excitation characteristics of the random laser.