Triplet–triplet annihilation upconversion in LAPONITE®/PVP nanocomposites: absolute quantum yields of up to 23.8% in the solid state and application to anti-counterfeiting

Abstract

The low quantum efficiency in the solid phase and the highly efficient quenching by oxygen are two major weaknesses limiting the practical applications of triplet-triplet annihilation (TTA) upconversion (UC). Herein,...

Microstructure-driven annihilation effects and dispersive excited state dynamics in solid-state films of a model sensitizer for photon energy up-conversion applications

“…In particular, a striking TTA-UC PL quantum yield (PLQY UC ) of 8% (out of maximum 50%) was reported for optimized large-area DPA:PtOEP lms 22 that can be further improved with the aid of ceramic-based nanocomposite frameworks. 23 Following the demonstration of TTA-UC in the solid state, [24][25][26] it was realized that several key challenges rst needed to be overcome before employing TTA-UC in technologically important bioinspired light-harvesting devices. The immobilization of sensitizer and emitter species in the spatially conned environment of a solid composite system enhances the occurrence of parasitic reabsorption of the emitter TTA-UC luminescence by the sensitizer component.…”

“…In particular, a striking TTA-UC PL quantum yield (PLQY UC ) of 8% (out of maximum 50%) was reported for optimized large-area DPA:PtOEP films 22 that can be further improved with the aid of ceramic-based nanocomposite frameworks. 23 …”

Photoprinting and expansion-induced erasure with supramolecular hydrogels crosslinked by pseudorotaxanation

“…We have been interested in supramolecular photochemistry based on host–guest complexation 14–17 and discovered photoprintable supramolecular gels and supramolecular photowriting. 18–20 We have demonstrated that tetraammonium-bearing axle molecules could lock a cyclodextrin (CD) molecule at the middle of the axle by stoppering the two terminals with two cucurbit[6]urils (CB[6]). 21–25 The [4]pseudorotaxanes thus formed showed significantly enhanced binding affinities for CD due to the inter-CB–CD hydrogen bonding.…”

Solvent-free temperature gradient melt formation of efficient visible-to-UV photon upconversion organic films with subsolar threshold and over 100 h photostability in air

“…To date, after some early works that embedded chromophores into polymers, 13,14 solid-state UC has been intensively investigated. 15–18 However, no UV–UC solids with an excitation threshold comparable with or lower than terrestrial solar intensity have been reported. 14,18…”