Stimuli-responsive solid-state emission from o-carborane–tetraphenylethene dyads induced by twisted intramolecular charge transfer in the crystalline state was demonstrated.

Realizing a high luminescence dissymmetry factor (glum) is a paramount yet challenging issue in the research field of circularly polarized luminescence (CPL). Here, we reported a novel set of organic conjugated systems with twisted intramolecular charge transfer (TICT) characteristics based on conjugated o-carborane-binaphthyl dyads composing of binaphthyl units as chiral electron donors and o-carborane units as achiral electron acceptors, demonstrating intense CPL with large glum values. Interestingly, single-crystalline o-1 exhibited a high-level brightness and a large glum factor as high as +0.13, whereas single-crystalline o-2 processed a relatively low brightness with a decreased glum value to -0.04. The significant diversity of CPL-active properties was triggered by the selective introduction of o-carborane units onto the binaphthyl units. Benefiting from the large magnetic dipole transition moments in TICT states, the CPL activity of TICT o-carborane-based materials exhibited amplified circular polarization. This study provides an efficient molecular engineering strategy for the rational design and development of highly efficient CPL-active materials.

Stimuli-responsive circularly polarized luminescence (CPL) was successfully achieved through fine-tuning the conformation of a perylenyl dyad by using external stimuli. Monomer CPL was clearly detected from an inherent achiral monochromophore system in a simple perylene-carbazole dyad, and concentration-dependent CPL was observed from 'good solvent', giving an excimer-like CPL emission with a peak maximum at 643 nm. Moreover, the CPL bands depended on the aggregated state, which was identical to the emission changes in the THF-HO system. It is noteworthy that the perylene-carbazole dyad emitted efficient CPL in thin films even without annealing processes. The specific perylenyl-carbazole structure plays a crucial role in CPL in response to the external environment. This novel molecular design strategy opens up a new perspective for the future development of smart CPL-active organic dyads.

Circularly polarized luminescence from a boron ketoiminate-based π-conjugated polymer was successfully realized at the unimolecular level via conformational locks that blocked the intramolecular rotations.

Two novel triphenylamine-o-carborane dyads with donor-acceptor architectures were designed and synthesized. The photophysical properties were thoroughly investigated. The results demonstrated that triphenylamine-o-carborane dyads presented locally excited (LE) emission and twisted intramolecular charge transfer (TICT) induced emission in various polar solvents, in which LE emission was not dependent on the solvent polarities and TICT emission was consistent with the solvent polarities. The solvent-dependent TICT emission with a large bathochromic shift exhibited a dramatic decrease in emissive efficiency with increasing the solvent polarity. More importantly, the triphenylamine-ocarborane dyads in solid states exhibited highly efficient ICT emissions, in which the ICT characteristics were confirmed by the experimental data and the density function theory (DFT) calculation results.

Tuning the circularly polarized luminescence (CPL) is a paramount yet challenging issue in the research field of chiral materials. Here, the chiral supramolecules were constructed with a chiral inducer LL-diphenylalanine (LPFF) and a triphenyl-1,3,5triazine-derived achiral molecule (DMAC-TRZ) to generate differentiated aggregates, giving rise to tunable responses of CPL. Specifically, the well-defined supercrystallines had an exceptional superior CPL emission located at 485 nm with a large luminescence dissymmetry factor (g lum ) value as high as +0.16, whereas the formed organic gel possessed a relatively strong CPL emission peaked at 495 nm with a g lum value of −0.04 in respect to the water fraction about 50%. The distinguished g lum value was assigned to the choice of spatial arrangement of the πchromophores of DMAC-TRZ responding to the volume water fraction in the H 2 O/DMSO system, resulting in a tunable g lum value. This strategy provides an efficient way to regulate CPL signals by modulating the π-stacking way of organic materials responding to external stimuli.

Molecular motions are closely associated with the behaviors and properties of organic materials. However, monitoring molecular motions is challenging. Herein, a chiral supramolecular system consisting of L-/D-phenylalanine (LPF/ DPF) as a chiral inducer and an achiral tetraphenylethene derivative (TPEF) as a molecular rotor has been proposed and explored for real-time discriminating the supramolecular motions by the visualization of circularly polarized luminescence (CPL) signal variations. Derived from the ordered molecular motions of TPEF induced by LPF/DPF, highly organized aggregates have been progressively assembled in a controlled manner with differentiated morphologies, including spherical particles, one-dimensional fibers, and floor-shaped supercrystals. Notably, increasing level of ordered aggregates, in turn, led to quenching emissions, while the CPL signals have been dramatically amplified accompanying by a sharp enhancement of luminescence dissymmetry factors (g lum ) from nearly 0 to À 0.1. The significant amplification of CPL is attributed to the ordered aggregates of supramolecules, leading to the decrease of electric transition dipole moments in supramolecular system. As a result of the chiral supramolecular motions powered by supramolecular crystallization, the supramolecular motions are conveniently discriminated by visual CPL signal variation with an enhancement of g lum value from 0 to À 0.1 in real time.

Ag/Co/B tri-doped TiO2/SiO2 film was prepared by the sol–gel method, and the structure and properties of this film were characterized by the X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) test method, field emission scanning electron microscopy (FE-SEM), differential thermal analysis-thermogravimetry (DTA-TG), photoluminescence (PL), and UV-visible diffuse reflectance spectrum (UV-vis DRS). XRD results indicated that the film structure of this film conforms to the anatase single crystal form. The presence of SiO2 can inhibit the formation of brookite and prevent the conversion of anatase into rutile. BET and FE-SEM results revealed that the film had a higher specific surface area and smaller grain size compared with pure TiO2 film. DTA-TG results exposed that the film had excellent thermal stability at 450[Formula: see text]C. Due to the spectacular adsorption capacity of SiO2 and the Schottky barrier formed between Ag and TiO2, this film improved the h[Formula: see text]/e[Formula: see text] separation efficiency and optical absorption performance showed by PL results. UV-vis DRS results displayed that the band gap energy (2.47 eV) of the film was clearly lower than that of pure TiO2 film, due to the intermediate energy levels generated by Co and B ions doping. The photocatalytic activity of the film was verified by ultraviolet and visible light degradation experiments of two different organic pollutants. The experimental results exhibited that the film had excellent photocatalytic degradation ability and stability. Ultimately, a possible synergistic mechanism of photocatalysis was proposed in this paper.