Amplified Heavy-Atom Free Phosphorescence from meta-Dimethoxy Difluoroboron β-Diketonate Charge-Transfer Materials

Abstract

Difluoroboron β-diketonate materials are used for biomedical oxygen-sensing applications. These fluorophores show both fluorescence (F) and phosphorescence (P) when the dye is embedded in a polymer matrix. The fluorescence is insensitive to oxygen quenching, while the phosphorescence changes intensity depending on the oxygen concentration. This enables oxygen quantification by ratiometric methods with good spatial and temporal resolution. Here, we produce ratiometric-capable oxygen sensors without the need of a heavy atom. This is achieved by substituting methoxyl groups at the meta positions of an aromatic ring, dramatically influencing the electronic transitions of the fluorophore. Altering the aromatic group on the opposing ring tailors the absorption wavelength, luminescence colors, and relative fluorescence to phosphorescence ratio (F/P), which are important for oxygen sensing. The phosphorescence lifetimes are also hundreds of milliseconds long, achieving ultra-sensitivity to oxygen. This study presents the synthesis, optical characterization in solution and polylactide blends, and computational analysis of 3,5-dimethoxy-difluoroboron β-diketonate materials as oxygen-sensing materials.

Manipulation of Triplet Excited States in Two‐Component Systems for High‐Performance Organic Afterglow Materials

“…Fraser and Zhang reported RTP behaviors of polylactic acid (PLA) systems with end‐capped difluoroboron β‐diketonate (BF 2 bdk) moieties [18] . RTP properties have also been observed by doping BF 2 bdk compounds into PLA matrices [66] . These polymer‐based RTP systems exhibited film‐forming capability and can be processed into aqueous dispersion with the aid of surfactant.…”

“…[18] RTP properties have also been observed by doping BF 2 bdk compounds into PLA matrices. [66] These polymer-based RTP systems exhibited film-forming capability and can be processed into aqueous dispersion with the aid of surfactant. The PLA matrices can inhibit intramolecular motion of BF 2 bdk triplet states, and meanwhile still allow oxygen permeation and diffusion.…”

Room temperature tunable multicolor phosphorescent polymers for humidity detection and information encryption

“…53 In terms of materials containing BF 2 bdks, this is reected in the different phosphor loadings. 44,54 Clearly, just as the uorescence emission of BF 2 bad red-shied with increasing solvent polarity, the uorescence emission wavelength of SPAP also showed a bathochromic shi from 468 nm (SPAP(1/100)) to 523 nm (SPAP(1/10)) as the BF 2 bad content increased which accompanied by the luminescence color turned from blue to green under environment conditions, and the spectra became broader. The RTP emission wavelength of SPAP showed the similar trend as the uorescence emission.…”

“…38,39 Aer Fraser's group rst reported the RTP of BF 2 bdks induced by coupling with poly(lactic acid), 40 emission color tuning for RTP materials based on BF 2 bdks has been investigated, while persistent RTP is restricted to inert conditions which limits the application of BF 2 bdks. [41][42][43][44] Herein, we proposed a new strategy to prepare a singlephosphor amorphous polymer (abbreviated as SPAP) with efficient RTP emission under ambient conditions via combining BF 2 bdks (named as BF 2 bad) and acrylamide monomer (Scheme 1a). Where the chemical crosslinking structures and high-density hydrogen bonds between polyacrylamide (PAM) chains are devised as the effective method to restrict molecular motion (Scheme 1b) of BF 2 bdks and polymer chains.…”

Asymmetric-donor (D2D2′)–acceptor (A) conjugates for simultaneously accessing intrinsic blue-RTP and blue-TADF

“…Single-component organic luminescent materials (SCOLMs) that show emission features with high photoluminescence quantum yield (PLQY) utilizing both singlet and triplet excited states have attracted increasing attention for their potential use in organic chemical sensing, 1,2 and bio-imaging 3 (Fig. 1).…”