Disorder‐Enhanced Charge‐Transfer‐Mediated Room‐Temperature Phosphorescence in Polymer Media

Abstract

Room‐temperature phosphorescence (RTP) polymers have important applications for biological imaging, oxygen sensing, data encryption, and photodynamic therapy. Despite the many advantages polymeric materials offer such as great control over gas permeability and processing flexibility, disorder is traditionally considered as an intrinsic negative impact on the efficiency for embedded RTP luminophores, as various allowed thermal motions could quench the emitting states. However, we propose that such disorder‐enabled freedoms of microscopic motions can be beneficial for charge‐transfer‐mediated RTP, which is facilitated by molecular conformational changes among different electronic transition states. Using the “classic” pyrene‐aniline excimer as an example, we demonstrate the mutual enhancement of red/near‐infrared and green RTP emissions from the pyrene and aniline moieties, respectively, upon doping of the aniline polymer with trace pyrene derivatives. In comparison, a pyrene‐doped crystal formed with the same aniline structure exhibits only charge‐transfer fluorescence with no red or green RTP observed, suggesting that order suppresses the RTP channels. The proposed polymerization strategy may be used as a unified method to generate multi‐emissive polymeric RTP materials from a vast pool of known and unknown exciplexes and charge‐transfer complexes.

Achieving Colorful Ultralong Organic Room-Temperature Phosphorescence by Precise Modification of Nitrogen Atoms on Phosphorescence Units

“…Bd and BCz-1 give out (photoactivated) orange ultralong phosphorescence , in a PMMA film at room temperature; BCz, N-1 and N-2 ,, all emit (photoactivated) green ultralong phosphorescence in a PMMA film at room temperature. There is no doubt that phosphorescence color is closely related to the molecular structures of Phosphorescence Units . − However, the internal structure–function relationship between phosphorescence color and the molecular structure of the Phosphorescence Unit is still unclear and should be paid close attention to. − …”

Organic Chameleon: Fluorescence, Phosphorescence and Radical Afterglow Triple Emission from Naphthylimide Functionalized Triphenylphosphine Derivatives

“…Furthermore, removal of the 365 nm UV source also exhibits an orange-yellow afterglow visible to the naked eye, which is consistent with the timedependent transient spectra (Figure 5c), suggesting that the TPP-o-3OMe-NMI-Br@PMMA films have photo-activated energy-transferring radical long afterglow properties. [22] It is worth mentioning that with the increasing doping concentration of TPP-o-3OMe-NMI-Br in PMMA (from 0.3% to 7.0%), their photoactivated UV-vis absorption spectra at 390-500 nm were enhanced (Take 0.5%, 2%, 3% as an example, Figure S18d-f, Supporting Information), while the long afterglow photoactivation time was gradually shortened (from 30 to 2 s) and accompanied by interesting fluorescence changes (purple to pink, Figure 5d), suggesting that multicolor fluorescence and time-dependent orange-yellow long afterglow emission can be modulated by modulating the doping ratio, the phenomenon is consistent with the steady-state spectrum (Figure S19, Supporting Information). We speculate that this phenomenon of photo-activated colorful fluorescence changes may arise from different luminophores in the molecule.…”

Two new Cd-based metal–organic frameworks for afterglow detection of Fe3+ and NH3

“…Various long-lived RTP materials have been reported thus far, including organic compounds, carbon dots, polymers, and inorganic-organic hybrids. [26][27][28][29] Among them, metal-organic frameworks (MOFs), as a novel class of aerglow materials, have garnered signicant attention recently due to their coordination bond-reinforced rigid structures that effectively suppress molecular vibrations and minimize energy dissipation from excited states. 30 Furthermore, the uniform distribution of metal ions within the structure can effectively facilitate the ISC process.…”