Excitation-dependent organic phosphors exhibiting different luminescence colors for information anti-counterfeiting

Halide-containing organic persistent luminescent materials for environmental sensing applications

“…Internal and external heavy-atom effects promote the ISC (or RISC) process and radiative transitions from triplet excited states to ground states, leading to distinct OPL intensity and lifetimes for halogen substituted compounds with different SOC constants. 7,8,29,40–44 It brings great convenience to the OPL molecular design for different environmental sensing application. Generally, iodine-containing OPL materials exhibit high phosphorescence quantum yields with short lifetimes of about several milliseconds, while long emission lifetimes of about hundreds of milliseconds will be realized in chlorine substituted OPL derivatives.…”

“…Long persistent luminescence, which can be captured by the naked eyes even after removing the excitation light source, has received considerable attention in the applications of sensing, bioimaging, light emitting devices, and data encryption. 1–8 Compared with the traditional transition metal-based or rare earth-based persistent luminescent materials, organic persistent luminescent (OPL) materials have become the research focus in recent years (Scheme 1) due to their advantages of flexible molecular design, easy synthesis, and low toxicity and production cost. The OPL properties are proved to be influenced greatly by the generation and deactivation process of the triplet excitons, including the intersystem crossing (ISC) process from singlet excited states to triplet excited states and the nonradiative decay and quenching processes.…”

Host to regulate the T1–S1and T1–S0processes of guest excitons in doped systems to control the TADF and RTP emissions

“…Organic materials with persistent luminescence phenomena have attracted much attention in the fields of anti-counterfeiting, optical recording, and biological imaging. 1–15 However, both room-temperature phosphorescence (RTP)-type afterglow materials and thermally activated delayed fluorescence (TADF)-type afterglow materials face the problem of homogenization and monotonicity of the luminescence phenomenon. 16–23 Designing materials with both TADF and RTP, and further regulating and combining the two emissions, is an effective strategy to enrich the luminescence phenomenon of materials.…”

Efficient and tunable purely organic room temperature phosphorescence films from selenium-containing emitters achieved by structural isomerism

“…The development of metal-free purely organic room temperature phosphorescent (RTP) materials with long-lived triplet states and high phosphorescence efficiency has received increasing attention for their potential applications in biological imaging, 1–3 optical sensing, 4–6 anti-counterfeiting, 7–11 encryption, 12–14 and electroluminescence. 15–17 Although purely organic RTP materials possess the advantages of low toxicity and cost, facile synthesis and functionalization, and good processability compared to traditional organometallic complexes of heavy metals, 18–21 their intrinsically weak spin–orbit coupling (SOC) may slow down both the intersystem crossing (ISC) from the lowest excited singlet state (S 1 ) to the triplet states (T n ) and the radiative decay process of the emissive triplet states, which thus can be quenched easily by molecular motions (rotations and vibrations) or quenchers (oxygen and humidity).…”