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Acid‐catalysed Friedländer cyclization of 2‐aminobenzophenones with 1,2‐, 1,3‐, and 1,4‐cyclohexadiones, followed by aromatization, has been used to prepare dibenzophenanthrolines (DBPs) containing 1,10‐, 1,7‐ and 4,7‐phenanthroline units, whose optoelectronic properties have been compared. The LUMO energies for all isomers were similar but the 4,7‐isomers possessed significantly higher HOMOs than the other isomers, resulting in them having smaller HOMO‐LUMO energy gaps. Compared with 1,10‐DBP isomers, the emission of 1,7‐DBPs is strongly quenched due to efficient charge transfer. The 4,7‐DBP isomers show strongly enhanced photoluminescence due to excimer formation but appear to be less photostable due to their higher HOMO levels. Bis(phenylethynyl)‐substituted derivatives demonstrated improved solubility and stronger luminescence properties than their unsubstituted analogues. [ABSTRACT FROM AUTHOR]

Co2+ doped into 0D/2D heterostructure serves as the bridge of charge transfer of TiO 2 and g-C 3 N 4 by chemical bond at interface. [Co(bpy) 3 Cl 2 in the reaction system functions as cocatalyst and active site by accepting the electrons from heterogeneous photocatalyst to catalyze CO 2 reduction. • Co2+ doped 0D/2D TiO 2 quantum dots confined in g-C 3 N 4 (CoTiCN) heterostructure was prepared by in-situ pyrolysis of MOFs and urea. • Co2+ plays the role of the bridge of linking 0D TiO 2 and 2D g-C 3 N 4 at interface, sequentially, promotes charge transfer from g-C 3 N 4 to TiO 2. • [Co(bpy) 3 Cl 2 in the reaction system functions as cocatalyst by accepting electrons from photocatalyst to catalyze CO 2 reduction. Low charge separation efficiency is the critical limitation for solar-driven CO 2 conversion into chemicals fuels. Accelerating charge transfer in the interface of photocatalysts is an intriguing approach to suppress charge recombination. Herein, Co2+ doped 0D/2D TiO 2 quantum dots confined in graphitic carbon nitride (CoTiCN) heterostructure was prepared by in-situ pyrolysis of MOFs and urea. Co2+ serves as the bridge of linking 0D TiO 2 and 2D g-C 3 N 4 in the interface, and consequently accelerates charge transfer in the interface from 2D g-C 3 N 4 to 0D TiO 2. As a result, CO evolution rate for photocatalytic CO 2 reduction reached 290 μmol g−1 h−1, much higher than those of pure g-C 3 N 4 and TiO 2 /g-C 3 N 4. In addition, photocatalytic mechanism study indicates that [Co(bpy) 3 Cl 2 in the system functions as cocatalyst without any photocatalytic activity under visible light irradiation. Electron transfer occurs from heterogeneous photocatalyst to [Co(bpy) 3 Cl 2 , which acts as the electron transporter as active sites to catalyze CO 2 reduction into CO. This work provides an insight into the design of metal doped 0D/2D material towards visible light driven CO 2 reduction from the viewpoint of promoting charge transfer in the interface and the understanding of the photocatalytic mechanism of cocatalyst in system. [ABSTRACT FROM AUTHOR]

Realization of a single white light emission (WLE) dyad is important for various applications, in particular, in display and light devices. In this work, we developed two BODIPY-based dyads BDP-B2 and BDP-B4 containing coumarin fluorophore connected to the 8-position of pyridinium with different aliphatic spacers. We found that BDP-B2 could show WLE in water/DMSO mixture solution. Detailed photophysical studies demonstrated that the coumarin emission, charge transfer (CT) and energy transfer (ET) are responsible for the WLE. • BDP-B2 could show white-light emission (WLE) in polar water/DMSO mixed solution. • Coumarin emission, charge transfer (CT) and energy transfer (ET) are responsible for the WLE from BDP-B2. • BDP-B2 would achieve color tunability in large area (blue-green-orange) of CIE diagram. [ABSTRACT FROM AUTHOR]

A novel donor-acceptor-donor (D-A-D') type of BODIPY derivative BDP-1 was synthesized and its fluorescence properties were investigated. By delicate tuning various parameters, e. g. solvent, concentration, excitation wavelength, aggregates of BDP-1 display single component white light emission (WLE), and the CIE coordinate values could be optimized to (0.33, 0.32). Detailed photophysical analysis by use of time-resolved spectroscopy and model compounds demonstrated that aggregation and further balance between energy transfer (ET) and intramolecular charge transfer (CT) from different groups in BDP-1 resulted in coordinated three primary color emissions which led to single component WLE. • A novel BODIPY derivative (BDP-1) was synthesized and its spectra properties were measured. • Single component WLE was realized through adjusting the concentration of BDP-1 and radiation wavelength. • The WLE was ascribed to the balanced mechanism of ET and CT states controlled by the aggregation of BDP-1. [ABSTRACT FROM AUTHOR]

• 0D/2D heterostructures of oxygen deficient TiO 2 quantum dots confined in g-C 3 N 4 nanosheets (TiO 2- x /g-C 3 N 4) were prepared by in-situ pyrolysis. • Charge dynamics analysis indicate that interfacial charge transfer occurs from 2D-g-C 3 N 4 to 0D-TiO 2 in ultrafast time scale (<1 ps). The overall faster decay is assigned to shallow trapped charges in favor of electrons trapped by CO 2. • TiO 2- x /g-C 3 N 4 show high CO 2 adsorption ability enhanced visible light absorption, and efficient charge separation. • TiO 2- x /g-C 3 N 4 exhibit 5 times higher CO evolution than that of pristine g-C 3 N 4 under visible light irradiation. Two-dimensional graphitic carbon nitride (g-C 3 N 4) has been widely explored as a promising photocatalyst for solar CO 2 conversion. However, rapid charge recombination and low visible-light utilization are severely detrimental to photocatalytic CO 2 conversion. Zero-dimensional/two-dimensional (0D/2D) heterostructures are considered the promising materials with size tunability and enhanced charge separation efficiency for photocatalysis. Herein, a 0D/2D heterostructure of oxygen vacancy-rich TiO 2 quantum dots confined in g-C 3 N 4 nanosheets (TiO 2- x /g-C 3 N 4) was prepared by in-situ pyrolysis of NH 2 -MIL-125 (Ti) and melamine. Charge dynamics analysis by time-resolved photoluminescence (tr-PL) and femtosecond and nanosecond pump-probed transient absorption (TA) spectra revealed that charges transfer occured from 2D-g-C 3 N 4 to 0D-TiO 2 at an ultrafast subpicosecond time scale (<1 ps) through the intimate interface. The overall fast decay of the charge carriers was attributed to interfacial charge transfer, which was accompanied by recombination relaxation mediated by shallow trapped sites. Ultrafast interfacial charge transfer greatly promoted charge separation and electrons in shallow trapped sites were easily trapped by CO 2. In addition, combining with the synergetic advantage of strong visible light absorption, high CO 2 adsorption and large surface area, TiO 2- x /g-C 3 N 4 exhibited a superior CO evolution rate of 77.8 μmol g−1 h−1, roughly 5 times that of pristine g-C 3 N 4 (15.1 μmol g−1 h−1). This work provides in-depth insights into optimizing the heterojunction for robust solar CO 2 conversion. [ABSTRACT FROM AUTHOR]