Förster Resonance Energy Transfer and Enhanced Emission in CsPbBr Nanocrystals Encapsulated in Silicon Nano-Sheets for Perovskite Light Emitting Diode Applications.

Encapsulating CsPbBr quantum dots in silicon nano-sheets not only stabilizes the halide perovskite, but also takes advantage of the nano-sheet for a compatible integration with the traditional silicon semiconductor. Here, we report the preparation of un-passivated CsPbBr ellipsoidal nanocrystals and pseudo-spherical quantum dots in silicon nano-sheets and their enhanced photoluminescence (PL). For a sample with low concentrations of quantum dots in silicon nano-sheets, the emission from CsPbBr pseudo-spherical quantum dots is quenched and is dominated with Pb ion/silicene emission, which is very stable during the whole measurement period.

Selective CW Laser Synthesis of MoS and Mixture of MoS and MoO from (NH)MoS Film.

Very recently, the synthesis of 2D MoS and WS through pulsed laser-directed thermolysis can achieve wafer-scale and large-area structures, in ambient conditions. In this paper, we report the synthesis of MoS and MoS oxides from (NH)MoS film using a visible continuous-wave (CW) laser at 532 nm, instead of the infrared pulsed laser for the laser-directed thermolysis. The (NH)MoS film is prepared by dissolving its crystal powder in DI water, sonicating the solution, and dip-coating onto a glass slide.

Fabrications of twisted moiré photonic crystal and random moiré photonic crystal and their potential applications in light extraction.

Twisted moiré photonic crystal is an optical analog of twisted graphene or twisted transition metal dichalcogenide bilayers. In this paper, we report the fabrication of twisted moiré photonic crystals and randomized moiré photonic crystals and their use in enhanced extraction of light in light-emitting diodes (LEDs). Fractional diffraction orders from randomized moiré photonic crystals are more uniform than those from moiré photonic crystals.

Enhanced Photoluminescence and Prolonged Carrier Lifetime through Laser Radiation Hardening and Self-Healing in Aged MAPbBr Perovskites Encapsulated in NiO Nanotubes.

Organic-inorganic perovskites hold great promise as optoelectronic semiconductors for pure color light emitting and photovoltaic devices. However, challenges persist regarding their photostability and chemical stability, which limit their extensive applications. This paper investigates the laser radiation hardening and self-healing-induced properties of aged MAPbBr perovskites encapsulated in NiO nanotubes (MAPbBr@NiO) using photoluminescence (PL) and fluorescence lifetime imaging (FLIM).

Holographic Fabrication of 3D Moiré Photonic Crystals Using Circularly Polarized Laser Beams and a Spatial Light Modulator.

A moiré photonic crystal is an optical analog of twisted graphene. A 3D moiré photonic crystal is a new nano-/microstructure that is distinguished from bilayer twisted photonic crystals. Holographic fabrication of a 3D moiré photonic crystal is very difficult due to the coexistence of the bright and dark regions, where the exposure threshold is suitable for one region but not for the other.

Holographic fabrication of octagon graded photonic supercrystal and potential applications in topological photonics.

Novel optical properties in graded photonic super-crystals can be further explored if new types of graded photonic super-crystals are fabricated. In this paper, we report holographic fabrication of graded photonic super-crystal with eight graded lattice clusters surrounding the central non-gradient lattices through pixel-by-pixel phase engineering in a spatial light modulator. The prospect of applications of octagon graded photonic super-crystal in topological photonics is discussed through photonic band gap engineering and coupled ring resonators.

Holographic fabrication of graded photonic super-quasi-crystals with multiple-level gradients.

Photonic quasi-crystals and photonic crystals with certain degrees of disorder can have a broadband light-matter interaction. In this paper, we present the holographic fabrication of graded photonic super-quasi-crystals through pixel-by-pixel phase pattern engineering using a spatial light modulator. Using the same phase pattern arranged in a decagon, we have fabricated graded photonic super-quasi-crystals with five-fold symmetry and multiple levels of gradients and graded photonic super-crystals with rectangular unit super-cells, depending on the Fourier filter.

Universal method for creating optically active nanostructures on layered materials.

The ability to form patterned surface nanostructures has revolutionized the miniaturization of electronics and led to the discovery of emergent behaviors unseen in macroscopic systems. However, the creation of such nanostructures typically requires multiple processing steps, a high level of technical expertise, and highly sophisticated equipment. In this work, we have discovered a simple method to create nanostructures with control size and positioning in a single processing step using a standard scanning electron microscope.