Morphological appearances and photo-controllable coloration of dye-doped cholesteric liquid crystal/polymer coaxial microfibers fabricated by coaxial electrospinning technique.

This study systematically investigates the morphological appearance of azo-chiral dye-doped cholesteric liquid crystal (DDCLC)/polymer coaxial microfibers obtained through the coaxial electrospinning technique and examines, for the first time, their photocontrollable reflection characteristics. Experimental results show that the quasi-continuous electrospun microfibers can be successfully fabricated at a high polymer concentration of 17.5 wt% and an optimum ratio of 2 for the feeding rates of sheath to core materials at 25 °C and a high humidity of 50% ± 2% in the spinning chamber. Furthermore, the optical controllability of the reflective features for the electrospun fibers is studied in detail by changing the concentration of the azo-chiral dopant in the core material, the UV irradiation intensity, and the core diameter of the fibers. Relevant mechanisms are addressed to explain the optical-control behaviors of the DDCLC coaxial fibers. Considering the results, optically controllable DDCLC coaxial microfibers present potential applications in UV microsensors and wearable smart textiles or swabs.

Wavelength-Tunable and Highly Stable Perovskite-Quantum-Dot-Doped Lasers with Liquid Crystal Lasing Cavities.

This study applies a low-cost solvothermal method to synthesize all-inorganic (lead-free cesium tin halide) perovskite quantum dots (AIPQDs) and to fabricate AIPQD-doped lasers with cholesteric liquid crystal (CLC) lasing cavities. The lasers present highly qualified lasing features of low threshold (150 nJ/pulse) and narrow line width (0.20 nm) that are attributed to the conjunction of the suppression of photoluminescence (PL) loss caused by the quantum confinement of AIPQDs and the amplification of PL caused by the band-edge effect of the CLC-distributed feedback resonator. In addition, the lasers possess highly flexible lasing-wavelength tuning features and a long-term stability under storage at room temperature and under high humidity given the protective role of CLC. These advantages are difficult to confer to typical light-emitting perovskite devices. Given these merits, the AIPQD-doped CLC laser device has considerable potential applications in optoelectronic and photonic devices, including lighting, displays, and lasers.