Perovskite quantum dots (QDs) have gained significant attention for both fundamental research and commercial applications because of their outstanding optoelectronic properties and tremendous application potentials. Reducing defect density in all-inorganic perovskite QDs is of great importance for performance enhancement. In this work, it is found that the UV-NIR femtosecond laser pulse treatments could increase the photoluminescence quantum yield (PLQY) of the CsPbBr 3 perovskite QDs from 71 to 95%. Such an enhancement could be attributed to decrease of the defects after laser exposure, which is consistent with its red-shifted PL and other characterization results. Furthermore, the dynamics of energy transfer from exciton to trapping in irradiated CsPbX 3 QDs are studied to gain an insight into the relative strength of exciton-trapping exchange coupling. The results confirm that the trapping defects are decreased by laser irradiation, and the mechanism leading to the enhancement of PLQY is revealed. In addition, the enhanced stability of laser-irradiated CsPbX 3 QDs is also testified. Finally, the application of laser-treated perovskite QDs in the liquid crystal display (LCD) backlight film is successfully demonstrated. It is further anticipated that this mechanism is helpful for the design of perovskite-based optoelectronic applications such as LCD technology and light-emitting devices.

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A compact, all-fiberized multiwavelength thulium-doped fiber laser based on a micro fiber-optic Fabry-Perot interferometer (FPI) and a nonlinear optical loop mirror (NOLM) has been demonstrated. The FPI with a free spectral range of ∼26 nm was used as an effective wavelength selective filter, which was constructed by splicing a ∼71.4-μm long air-filled hollow-core fiber with single-mode fibers at both ends. An NOLM, served as an amplitude equalizer, was used for stabilizing multiwavelength laser operation. Besides switchable single-wavelength operations (

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In recent years, using two-dimensional (2D) materials to realize broadband photodetection has become a promising area in optoelectronic devices. Here, we successfully synthesized SnSe nanosheets (NSs) by a facile tip ultra-sonication method in water-ethanol solvent which was eco-friendly. The carrier dynamics of SnSe NSs was systematically investigated via a femtosecond transient absorption spectroscopy in the visible wavelength regime and three decay components were clarified with delay time of τ1 = 0.77 ps, τ2 = 8.3 ps, and τ3 = 316.5 ps, respectively, indicating their potential applications in ultrafast optics and optoelectronics. As a proof-of-concept, the photodetectors, which integrated SnSe NSs with monolayer graphene, show high photoresponsivities and excellent response speeds for different incident lasers. The maximum photo-responsivities for 405, 532, and 785 nm were 1.75 × 104 A/W, 4.63 × 103 A/W, and 1.52 × 103 A/W, respectively. The photoresponse times were ~22.6 ms, 11.6 ms, and 9.7 ms. This behavior was due to the broadband light response of SnSe NSs and fast transportation of photocarriers between the monolayer graphene and SnSe NSs.