Achieving Color‐Tunable and Time‐Dependent Organic Long Persistent Luminescence via Phosphorescence Energy Transfer for Advanced Anti‐Counterfeiting

Abstract

Organic ultralong room‐temperature phosphorescence (RTP) materials have promising applications in anti‐counterfeiting. To improve the encryption level, the exploration of organic materials with tunable solid‐state long persistent luminescence is in urgent need. Herein, a series of organic ultralong RTP polymeric systems are prepared by doping versatile indolocarbazole isomers into the poly(vinyl alcohol) (PVA) matrix. Notably, the doping film 11,12‐ICz@PVA exhibits excellent RTP property with an ultralong lifetime of 2.04 s and a high phosphorescence quantum yield of 44.1%. Theoretical calculations reveal that this excellent RTP property can be attributed to the strong electrostatic attraction resulting from the synergistic double hydrogen‐bond between the isomer 11,12‐ICz and PVA matrix. More impressively, color‐tunable and time‐dependent long persistent luminescence is successfully achieved through efficient phosphorescence energy transfer between the indolocarbazole isomers with ultralong blue RTP emissions and commercially available fluorescent dyes with emission colors ranging from green to red doped into the PVA matrix. Besides, diversified encryption patterns are fabricated to demonstrate the promising applications of these water‐soluble doping PVA systems with tunable solid‐state persistent luminescence in advanced anti‐counterfeiting technology.

Crystal structures, dual-state emissions and polymer-based doped room-temperature phosphorescence of 8-benzyloxyisoquinoline derivatives

“…8a and b), respectively, indicating that the delayed emissions should originate from phosphorescence. 11 The delayed lifetimes and phosphorescence quantum yields of PMMA/IQ-H and PMMA/ IQ-Me are determined to be 72 and 96 ms (Fig. S12a and b †), and 2.0 and 2.9%, respectively.…”

Organic Host‐Guest Materials with Bright Red Room‐Temperature Phosphorescence for Persistent Bioimaging†

“…Organic room‐temperature phosphorescence (RTP) materials have attracted immense attention due to their peculiar photophysical process and potential applications in advanced printable and writable security inks, [ 1‐4 ] high‐resolution bioimaging, [ 5‐7 ] microenvironment oxygen visual sensing and quantitative detection. [ 8‐11 ] Several attempts have been made to develop high‐performance RTP materials, including the introduction of heavy atoms or halogen/hydrogen bonding, [ 12‐17 ] doping in a rigid matrix, [ 18‐26 ] construction of metal‐organic frameworks, [ 27‐28 ] and ionic‐π interactions.…”

Förster resonance energy transfer involving the triplet state

“…For example, indolocarbazole isomers doped in a poly(vinyl alcohol) matrix exhibited strong cyan RTP emission ( Φ p = 5%–44%) with a long lifetime (0.38–2.04 s). 89 In combination with the fluorescent dye, the afterglow emission color was tuned from cyan to green to red, and the potential for anti-counterfeiting applications was demonstrated. Another paper reported intramolecular RT FRET T-S in a copolymer containing an afterglow host and a narrowband A core, leading to narrowband afterglow emission from the A core via RT FRET T-S .…”