Full-type photoluminescence from a single organic molecule for multi-signal temperature sensing

Zhang

et al. 2022

Adv Funct Materials

Long‐lived room temperature phosphorescence (RTP) systems have become a research focus in the field of functional materials due to their fascinating luminescence properties. However, it is still an enormous challenge to realize RTP under ambient conditions, since RTP can be quenched easily by molecular oxygen. Herein, two polymer acceptors containing triphenyl phosphonium bromide salt are designed and synthesized successfully. They are then doped into a poly(methyl methacrylate) matrix with donor molecules to form flexible films with long‐lived RTP. Interestingly, the long‐lived RTP performance is highly dependent on the grafting rate of the polymers. Upon increasing the grafting rate, the aggregation degree of polymer acceptors increases, further inhibiting the molecular movement in the aggregates and reducing nonradiative vibration deactivation of triplet excitons for achieving green long‐lived RTP. Meanwhile, the visualization of real information and complete pattern after 365 nm UV irradiation is demonstrated based on these long‐lived RTP systems, presenting application potential toward dynamic multilevel information encryption and display devices. This work provides an innovative principle for the activation of long‐lived RTP in the polymeric systems under ambient conditions.

Section: Introductionmentioning

confidence: 99%

Photo‐Induced Dynamic Room Temperature Phosphorescence Based on Triphenyl Phosphonium Containing Polymers

Zhang

et al. 2022

Adv Funct Materials

“…Metal-free room-temperature phosphorescent (RTP) materials with unique advantages of low cost, negligible toxicity, and easy synthesis have attracted more and more attention in recent years due to their potential applications in anti-counterfeiting, − encryption, − optical sensing, − bioimaging, − and electroluminescence. − To realize efficient RTP emission, it is necessary not only to enhance the intersystem crossing (ISC) process to improve triplet exciton formation but also to suppress the non-radiative decay of triplet excitons. Until now, most highly efficient RTP materials are based on small molecular crystals, which can form rigid microenvironments to suppress non-radiative decay. − However, stringent preparation conditions and poor film-forming properties of these molecular crystals may restrict their real applications as RTP films.…”

Section: Introductionmentioning

confidence: 99%

Efficient Purely Organic Room-Temperature Phosphorescence from Selenium-Containing Conjugated Polymers for Signal-Amplified Oxygen Detection

et al. 2023

Purely organic room-temperature phosphorescent (RTP) polymers with good processability and flexibility over small molecular crystals are highly attractive. Although many non-conjugated polymers (non-CPs) with efficient RTP emission have been reported, the development of metal-free RTP CPs remains a formidable challenge. Herein, CPs with clear RTP emission in both doped and neat films are readily prepared by introducing a selenium-containing phenoselenazine unit into conjugated backbones. The resulting RTP CPs can achieve phosphorescence lifetimes ranging from microseconds to milliseconds and phosphorescence quantum yields of up to 17.2% in film states, representing the highest value for metal-free CPs. Moreover, these RTP polymer films can be used for ratiometric oxygen detection due to their sensitive RTP emission to oxygen. Remarkably, for the first time, these metal-free CPs demonstrate significant phosphorescent signal amplification with a Stern–Volmer quenching constant (K SV) value of up to 5.54 × 10–3 ppm–1, which is 250 times higher than that of their molecule counterpart.

“…The research of organic luminescent materials has drawn great attention, because of their wide applications in bio-imaging, sensors, anti-counterfeiting and displays, etc. [1][2][3][4][5][6][7] With different luminescence properties, luminogens generally present different photophysical processes and applicable scenarios. For instance, thermally-activated delayed fluorescence (TADF) indicates a radiative transition of singlet excitons after undergoing intersystem crossing (ISC) and reverse intersystem crossing (RISC) between excited singlet and triplet states.…”

Section: Introductionmentioning

confidence: 99%

Exciplex-induced TADF, persistent RTP and ML in a host–guest doping system

Gao

Ren

et al. 2023

Mater. Chem. Front.