Synthesis and optical properties of doped CdS/lead halide perovskite nanostructures

The application of light-emitting devices, solar cells, spintronics, optical sensors, and new optoelectronic devices have attracted much attention. It's of significant importance to control the optical, electrical, magnetic properties of semiconductor nanomaterials by doping technique. Here, transition metal (TM) doped II-VI group semiconductor nanomaterials were studied by chemical vapor deposition. Besides, TM doped perovskite nanomaterials were prepared by solution method. The interaction between exciton and magnetic polaron in doped nanomaterials have been carefully studied. These research progress could provide the promising applications in spin related photonic and photoelectronic devices

Light Amplification in Fe-Doped CsPbBr₃ Crystal Microwire Excited by Continuous-Wave Laser

Electrically pumped halide perovskite laser diodes remain unexplored, and it is widely acknowledged that continuous-wave (CW) lasing will be a crucial step. Here, we demonstrate room-temperature amplified spontaneous emission of Fe-doped CsPbBr3 crystal microwire excited by a CW laser. Temperature-dependent photoluminescence spectra indicate that the Fe dopant forms a shallow level trap states near the band edge of the lightly doped CsPbBr3 microcrystal. Pump intensity-dependent time-resolved PL spectra show that the introduced Fe dopant level makes the electron more stable in excited states, suitable for the population inversion. The emission peak intensity of the lightly Fe-doped microwire increases nonlinearly above a threshold of 12.3 kW/cm2 under CW laser excitation, indicating a significant light amplification. Under high excitation, the uniform crystal structure and surface outcoupling in Fe-doped perovskite crystal microwires enhanced the spontaneous emission. These results reveal the considerable promise of Fe-doped perovskite crystal microwires toward low-cost, high-performance, room-temperature electrical pumping perovskite lasers

General Synthesis and White Light Emission of Diluted Magnetic Semiconductor Nanowires Using Single-Source Precursors

Because of the fundamental properties and possible applications in spin-based electronics and photonics, diluted magnetic semiconductor nanowires are actively pursued. Here we report a general and facile solution synthetic strategy to prepare colloidal diluted magnetic semiconductor nanowires through solution-liquid–solid (SLS) doping approach using single-source precursors. On the basis of this strategy, transition metal ions such as Mn and Eu doped CdS nanowires were successfully synthesized and characterized. The material characterizations demonstrated that the doping process is nucleation controlled. We further investigated the Mn doping effects on nanowire growth as well as their photoluminescence properties. The Mn doped CdS nanowires exhibit photoluminescence emission related to the excitonic magnetic polaron in CdS, single Mn2+ ion and Mn–S–Mn centers as well as trap states, evidenced by the time-resolved photoluminescence spectra and magnetic measurements. With the increase of Mn precursor that used in the doping process, the Mn2+ related emission becomes more pronounced. By tuning the doping concentration, white emissive doped CdS nanowires were achieved

Bosonic Lasing from Collective Exciton Magnetic Polarons in Diluted Magnetic Nanowires and Nanobelts

Exciton magnetic polarons (EMPs) are self-organized magnetic quasiparticles that can be formed by excitons in diluted magnetic semiconductors (DMSs). The optical response of EMPs in DMS microstructures is not yet well understood because it is affected by many competing factors, including spin-dependent exchange interactions, phonon coupling, and collective and nonlinear effects upon the dopant concentration and structural relaxation. Here, we report on lasing from collective EMP states in Co­(II)-doped CdS nanowires (NWs) and nanobelts (NBs) that we interpret in terms of bosonic lasing, the spontaneous emission of radiation by a single quantum state macroscopically populated by bosonic quasiparticles. The lasing threshold coincides with the appearance of ferromagnetic domains, indicating an important role of spin ordering in the formation of coherent collective EMPs. These results pave the way to the realization of a new type of bosonic laser, different from exciton-polariton lasers, where formation of the bosonic condensate is possible due to the coupling of EMPs via the exchange interaction of exciton and magnetic ion spins

Probing Exciton Move and Localization in Solution-Grown Colloidal CdSe_<i>x</i>S_1–<i>x</i> Alloyed Nanowires by Temperature- and Time-Resolved Spectroscopy

Colloidal semiconductor nanowires are interesting materials with polarized optical feature for optoelectronics devices. Previously, we observed an interesting photoluminescence enhancement in colloidal alloyed CdSe_<i>x</i>S_1–<i>x</i> nanowires. In the present work, low temperature steady-state and time-resolved photoluminescence spectra were applied to understand the photoluminescence enhancement in these CdSe_<i>x</i>S_1–<i>x</i> alloyed nanowires. The band-edge emission and surface-defect emission of alloyed CdSe_<i>x</i>S_1–<i>x</i> nanowires, observed in low temperature photoluminescence spectra, show different changing trend with the variation of their composition. Moreover, the radiative lifetime for band-edge emission and surface-defect emission reveals an opposite changing trend with the variation of temperature. These findings suggest that the variation of photoluminescence quantum yields with composition is determined by the competition between exciton move and localization. If the carriers are localized in the interior of nanowires, the migration of photoinduced excitons to their surface will be prohibited, and more probability for radiative recombination at band edge occurred

Template-Free Synthesis of High-Yield Fe-Doped Cesium Lead Halide Perovskite Ultralong Microwires with Enhanced Two-Photon Absorption

Doping in perovskite is challenging and competitive due to the inherently fast growth mechanism of perovskite structure. Here, we demonstrate successful synthesis of high-yield Fe-doped cesium lead halide perovskite ultralong microwires (MWs) that have diameters up to ∼5 μm and lengths up to millimeters via an antisolvent vapor-assisted template-free method. Microstructure characterization confirms the uniformly doped Fe in the high-quality crystal perovskite MWs. Significantly, doping the Fe­(III) concentration can affect both the MW morphology and photoluminescence (PL). The band edge emission of the MW at variable excitation has been accounted for by the superposition and combination of optical transitions of nearby singlet, triplet, and magnetic polaronic excitons. High-quality two-photon PL emission and the enhanced nonlinear absorption coefficient of Fe-doped MWs have been experimentally demonstrated. This superhigh nonlinear absorption coefficient and high-quality optical properties endow it with promising applications in spin-related optical switching and optical limiting devices

Template-Free Synthesis of High-Yield Fe-Doped Cesium Lead Halide Perovskite Ultralong Microwires with Enhanced Two-Photon Absorption

Doping in perovskite is challenging and competitive due to the inherently fast growth mechanism of perovskite structure. Here, we demonstrate successful synthesis of high-yield Fe-doped cesium lead halide perovskite ultralong microwires (MWs) that have diameters up to ∼5 μm and lengths up to millimeters via an antisolvent vapor-assisted template-free method. Microstructure characterization confirms the uniformly doped Fe in the high-quality crystal perovskite MWs. Significantly, doping the Fe­(III) concentration can affect both the MW morphology and photoluminescence (PL). The band edge emission of the MW at variable excitation has been accounted for by the superposition and combination of optical transitions of nearby singlet, triplet, and magnetic polaronic excitons. High-quality two-photon PL emission and the enhanced nonlinear absorption coefficient of Fe-doped MWs have been experimentally demonstrated. This superhigh nonlinear absorption coefficient and high-quality optical properties endow it with promising applications in spin-related optical switching and optical limiting devices