Revealing Insight into Long-Lived Room-Temperature Phosphorescence of Host–Guest Systems

Abstract

The control of the emission properties of doping materials through molecular design makes organic materials potentially promising candidates for many optoelectronic applications and devices. However, organic doping systems with high quantum yields and persistent luminescence processes have rarely been reported, and their luminescence mechanisms are still not well established. Here we developed a series of purely organic heavy-atom-free doping systems. The guest molecules can dope either donor or acceptor matrixes, both leading to an enhanced fluorescence (Φ = 63−76%) and room-temperature phosphorescence (Φ = 7.6−14.5%, τ = 119−317 ms) under ambient conditions. XRD measurements and density functional calculations results indicated ultralong phosphorescence was determined by both the cocrystalline state and the energy levels between the host and guest materials. The doping materials are fairly stable to light, heat, and humidity. This work may provide unique insight for designing doping systems and expanding the scope of organic phosphorescence applications.

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

“…Such increase in the F P values and decrease in the RTP lifetimes may originate due to the strong intermolecular interactions between the dopant and the host material which contribute to the reduction of the nonradiative decay through vibrations. 41 Furthermore, the TRES measurements of 0.1% DPEPO films under ambient conditions are found to be similar to the results obtained in the PMMA films ( Fig. S23-S25, ESI †).…”

“…In addition, the molecular vibrations that readily increase the non-radiative pathways of the localized triplet excitons become another major bottleneck to harvest efficient phosphorescence yield. 36 To circumvent the above issues, crystal formation, 37,38 aggregation, 39,40 hostguest interactions 41 and deuteration 42 have been studied to reduce the nonradiative pathways under ambient conditions. To observe both blue-TADF (BTADF) and blue-RTP (BRTP) simultaneously with high PLQY from the SCOLMs under ambient conditions becomes a difficult task in the field of chemical physics.…”

Tunable Phosphorescence/Fluorescence Dual Emissions of Organic Isoquinoline‐Benzophenone Doped Systems by Alkoxy Engineering

“…Recently, our works have shown that the host molecule not only provides a rigid environment to restrict movement, but also contributes to the energy transfer of the guest molecule (Scheme 1). [7c, d] Herein, a new doped system with strong RTP property was developed through prediction and design, in which isoquinoline derivatives (IQL‐C n ) containing different alkoxy chains were selected as the guest molecules and cheap benzophenone (BPO) as the host molecule (Scheme 1). The guests were prepared from a simple three‐step procedure by using commercially available 2,6‐dimethyl‐4 H ‐pyran‐4‐one as the starting material according to Scheme S1 (in the Supporting Information) [8] .…”

Organic Room Temperature Phosphorescence Materials for Biomedical Applications

“…One is to facilitatie the intersystem crossing (ISC) from the lowest excited singlet state (S 1 ) to a triplet state (T n ) to populate the triplet excitons, and the other is to inhibit nonradiative transitions from the lowest excited triplet state (T 1 ) to the ground state (S 0 ). On the basic of these factors, researchers have proposed various strategies and methods to moldulate phosphorescent performance, such as intruduction of heavy atoms, [20][21][22] heteroatoms [23][24][25] and aromatic carbony [26][27] to boost SOC; while suppressing non-radiation of the triplet excitons by host-guest doping method [28][29][30][31] crystalization [32][33][34] and organic flameworks. [35][36][37] Therefore, developing metal-free organic luminescent materials with highly efficient room temperature phosphorescence has been becoming a hot topic in recent years.…”