Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation

Abstract

Achieving organic room-temperature phosphorescence (RTP) in a solvent-free liquid state is a challenging task because the liquid state provides a less rigid environment than the crystal. Here, we report that...

Halide-containing organic persistent luminescent materials for environmental sensing applications

“…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.…”

Modulating Room-Temperature Phosphorescence-To-Phosphorescence Mechanochromism by Halogen Exchange

“…In addition, we desymmetrized the C 2 -symmetrical BrTn structure. ( Tani et al, 2020 ; Komura et al, 2021 ) Notably, replacing one of the two Br atoms with a hydrogen atom led to the formation of a crystal that is isostructural with that of BrTn ( Tani et al, 2020 ). Interestingly, the crystal of the unsymmetrical diketone was non-emissive, which was attributed to the presence of voids that result from the volumetric difference between Br and H ( Figure 1B top).…”

Light-melting Diketone Crystal with ON-OFF-ON Luminescence Evolution

“…The resulting emission (max = 575 nm) was similar to that of the SCL state and can be ascribed to the RTP from the planar conformer (Figure 2A). 42 Note that the phosphorescence of the SCL state disappears at higher temperatures (lower than the melting point, which is 59.5 °C, see Figure S2). Therefore, the melting is not caused by heating.…”

“…Most notably, while the crystal consists of the poorly emissive skew conformer, the planar conformer is more stable in the excited state and is responsible for the RTP in the SCL state. 42,[46][47][48][49] Herein, using SO crystals, we demonstrate for the first time the phenomenon of PCMT with luminescence, which is reflective of the molecular environment and allows for the visualization of the local melting process in real time.…”

“…As reported previously, SO forms a kinetically super-stable SCL at room temperature. 42 Hence, its melting is a crystal-to-SCL transition, that is, a transition to the metastable phase. The resulting emission (max = 575 nm) was similar to that of the SCL state and can be ascribed to the RTP from the planar conformer (Figure 2A).…”