Delignification of wood and infiltration with alumina/polyvinylpyrrolidone nanofiber-reinforced nanocomposite toward photoluminescent smart window for detection and filtration of ultraviolet radiation

Novel photoluminescent hardwood that can change color under ultraviolet illumination was developed. Transparent wood templates with afterglow and photochromic properties were developed by infiltrating a mixture of electrospun alumina/polyvinylpyrrolidone nanofiber-reinforced polystyrene nanocomposite and rare-earth aluminate (REA) into a delignified hardwood. The REA pigment has excellent thermal stability and photostability. Avoiding aggregation of the pigment nanoparticles (NPs) while dispersing the REA nanopigment in an alumina nanofiber-reinforced pre-polymerized polystyrene is significant for the development of a transparent photoluminescent wood. The photoluminescence spectra and colorimetric data showed that the transparent wood switches to green under UV illumination. The REA pigment was synthesized by the solid-state method, whereas the REA nanopowder was developed by the top-down technology. A spinnable solution of polyvinylpyrrolidone/aluminum chloride was developed by the sol–gel method. EAN was then calcinated to provide alumina fibers with diameters of 50–200 nm. The pigment nanoparticles displayed diameters of 8–15 nm. The transparent wood that emitted light upon excitation at 375 nm displayed a strong emission peak at 518 nm. Improved water resistance and UV protection were observed with increasing the phosphor concentration.