Intramolecular Triplet–Triplet Annihilation Upconversion in 9,10-Diphenylanthracene Oligomers and Dendrimers

Abstract

An important challenge when developing materials for triplet–triplet annihilation upconversion (TTA-UC) is achieving efficient and well-functioning solid-state systems. We here explore the effect of intramolecular TTA in oligomers and dendrimers based on the 9,10-diphenylanthracene (DPA) chromophore. The macromolecules are sensitized using palladium porphyrin, both in solution and in solid poly­(methyl methacrylate) (PMMA), demonstrating a positive effect on overall upconversion in the solid state correlating with the well-controlled size of the DPA constructs. The UC kinetics is modeled and fit to steady-state and time-resolved emission data to give further insight into the intramolecular excited-state migration and annihilation in the macromolecular annihilator systems.

Ligand‐Tuneable, Red‐Emitting Iridium(III) Complexes for Efficient Triplet–Triplet Annihilation Upconversion Performance

“…In comparison, the upconversion performance was contrastingly low (≤1 %) for both dichloro species, [Ir(L3) 2 (bpy)]PF 6 and [Ir(L6) 2 (bpy)]PF 6 . Previous reports in the literature have highlighted high molar absorption coefficients in the visible region and long triplet excited‐state lifetimes as advantageous attributes for triplet sensitisers . It is notable that these complexes possess modest triplet‐state lifetimes and molar absorption values of around 5000 m −1 cm −1 in the visible region at λ ≈500 nm.…”

Tetraphenylethene 9,10‐Diphenylanthracene Derivatives – Synthesis and Photophysical Properties

“…Tetraphenylethene (TPE) and 9,10‐diphenylanthracene (DPA) are aromatic chromophores with well‐known photophysical properties that have found application as building blocks in dyes for biological imaging, chemical sensing and light harvesting . Anthracene is an exceptionally well‐studied organic fluorophore due to its high fluorescence quantum yield, strong light absorption, and its energetically useful triplet energy.…”

“…When substituted at the 9‐ and 10‐positions (e. g. DPA), anthracene derivatives have improved photostability and solubility, which has opened up new applications for this dye in singlet exciton fission, and triplet‐triplet annihilation upconversion (TTA‐UC) applications For studies of intramolecular TTA‐UC, DPA is considered a prototypical emitter and has been incorporated within linear and star‐shaped pendant polymers, oligomers and dendrimers …”

“…Tetraphenylethene (TPE) and 9,10-diphenylanthracene (DPA) are aromatic chromophores with well-known photophysical properties that have found application as building blocks in dyes for biological imaging, chemical sensing and light harvesting. [1,2,[3][4][5][6][7] Anthracene is an exceptionally well-studied organic fluorophore due to its high fluorescence quantum yield, strong light absorption, and its energetically useful triplet energy. When substituted at the 9-and 10-positions (e. g. DPA), anthracene derivatives have improved photostability and solubility, which has opened up new applications for this dye in singlet exciton fission, and triplet-triplet annihilation upconversion (TTA-UC) applications.…”

“…[8À 10] For studies of intramolecular TTA-UC, DPA is considered a prototypical emitter and has been incorporated within linear and star-shaped pendant polymers, oligomers and dendrimers. [4,[11][12][13] TPE is a well-known aggregation induced emission (AIE) backbone that is able to exhibit AIE behavior when coupled to a variety of chromophores. A series of luminogens composed of TPE and various aromatic hydrocarbons, such as pyrene, anthracene and naphthalene have been reported.…”