Self‐Adhesive, Isotropic, and All‐Wood Transparent Room Temperature Phosphorescent Laminates

Abstract Transparent wood has attracted considerable attention for its transparency, low thermal conductivity, and multi‐functionality, rendering it promising for optical materials. Transparent wood is prone to oxidative yellowing and is non‐degradable due to that the methods of producing transparent wood typically involve in impregnation with petroleum‐based polymers. In addition, poor compatibility between wood fibers and polymers always leads to complex processes and low yields for transparent wood. Here, an isotropic self‐adhesive all‐wood laminate is developed by delignification, oxidation‐reduction modification, and physical densification. Oxidation‐reduction modification endows abundant high‐density cross‐linking points, while further self‐assembly lamination enables forming a dense structure through strong hydrogen bond, leading to the transparent laminate with isotropic high mechanical properties, outstanding optical properties, and long afterglow emission simultaneously. The demonstrated isotropic transparent laminate obtains an optical transmittance ≈70%, while maintaining an optical haze ≈90%. The all‐wood transparent laminate featuring a tensile strength of 156.9 ± 9.0 MPa and 159.3 ± 23.7 MPa in the two perpendicular directions is characterized as significant isotropy. The transparent wood produced efficient afterglow RTP emission with a lifetime of ≈342 ms, which is competitive among similar wood‐based materials and exhibits great potential for the construction of smart optical materials.