Colorful Room-Temperature Phosphorescence Including White Afterglow from Mechanical Robust Transparent Wood for Time Delay Lighting

Abstract

The preparation of mechanical robust organic room-temperature phosphorescence (RTP) materials especially with white afterglow is attractive but rarely reported. Herein, a method to produce mechanical robust colorful RTP transparent wood (PTW) by infiltrating delignified wood with poly (vinyl alcohol) solutions containing arylboronic acids with various π conjugations is reported. The doubly rigid environment provided by the B─O covalent bonds and hydrogen bonds can stabilize the triplet excitons, leading to a ultralong lifetime of up to 2.13 s and excellent RTP emission stability (without obviously quenching over a month) of the target PTW. Besides, as a promising structural material for optical applications, the PTW shows combined advantages of multicolored persistent luminescence (from blue to green and then to red), good optical transmittance (≈90%), and striking mechanical strength (≈154 MPa). More importantly, by introducing appropriate amount of fluorescent dye rhodamine 6 G to the PTW with blue afterglow, white afterglow with a lifetime of 1.85 s is successfully achieve through triplet-to-singlet Förster resonance energy transfer. The PTW can function as afterglow window, anticounterfeiting label, and time delay lighting. This success paves the way for the development of mechanical robust, ecofriendly, and practical RTP materials.