Photoinduced Aryl Transfer from Imidazolyl-Quinoline π-Conjugated Systems.

Aryl transfer between heteroatoms was photochemically available through radical initiation followed by a bimolecular reaction. However, such an excited-state reaction has rarely been reported through a photoinduced intramolecular pathway in the π-conjugated systems. Herein, we found, for the first time, a clean photoinduced intramolecular aryl shift for imidazolyl-quinoline derivatives (imidazophenanthrene) and (imidazophenanthroline), of which the photoproducts are thermally reversible.

Hybrid Inorganic-Organic Complexes of Zn, Cd, and Pb with a Cationic Phenanthro-diimine Ligand.

The phosphonium-decorated phenanthro-imidazolyl pyridine ligand, Br, readily reacts with zinc(II) and cadmium(II) bromides to give inorganic-organic zero-dimensional compounds [ZnBr][ZnBr] () and [()CdBr][CdBr] (), respectively, upon crystallization. These salts are moderately fluorescent in the solid state under ambient conditions (λ = 458 nm, Φ = 0.11 for ; λ = 460 nm, Φ = 0.

Recognizing the Importance of Fast Nonisothermal Crystallization for High-Performance Two-Dimensional Dion-Jacobson Perovskite Solar Cells with High Fill Factors: A Comprehensive Mechanistic Study.

Two-dimensional (2D) Dion-Jacobson (DJ) perovskite solar cells (PSCs), despite their advantage in versatility of n-layer variation, are subject to poor photovoltaic efficiency, particularly in the fill factor (FF), compared to their three-dimensional counterparts. To enhance the performance of DJ PSCs, the process of growing crystals and hence the corresponding morphology of DJ perovskites are of prime importance. Herein, we report the fast nonisothermal (NIT) crystallization protocol that is previously unrecognized for 2D perovskites to significantly improve the morphology, orientation, and charge transport of the DJ perovskite films.

Blue Phosphorescence and Hyperluminescence Generated from Imidazo[4,5-b]pyridin-2-ylidene-Based Iridium(III) Phosphors.

Four isomeric, homoleptic iridium(III) metal complexes bearing 5-(trifluoromethyl)imidazo[4,5-b]pyridin-2-ylidene and 6-(trifluoromethyl)imidazo[4,5-b]pyridin-2-ylidene-based cyclometalating chelates are successfully synthesized. The meridional isomers can be converted to facial isomers through acid induced isomerization. The m-isomers display a relatively broadened and red-shifted emission, while f-isomers exhibit narrowed blue emission band, together with higher photoluminescent quantum yields and reduced radiative lifetime relative to the mer-counterparts.

Modulation of Perovskite Grain Boundaries by Electron Donor-Acceptor Zwitterions ,-Diphenylamino-phenyl-pyridinium-(CH) -sulfonates: All-Round Improvement on the Solar Cell Performance.

Inverted perovskite solar cells (PSCs) have attracted intense attention because of their insignificant hysteresis and low-temperature fabrication process. However, the efficiencies of inverted PSCs are still inferior to those of commercialized silicon solar cells. Also, the poor stability of PSCs is one of the major impedances to commercialization.

A new approach exploiting thermally activated delayed fluorescence molecules to optimize solar thermal energy storage.

We propose a new concept exploiting thermally activated delayed fluorescence (TADF) molecules as photosensitizers, storage units and signal transducers to harness solar thermal energy. Molecular composites based on the TADF core phenoxazine-triphenyltriazine (PXZ-TRZ) anchored with norbornadiene (NBD) were synthesized, yielding compounds PZDN and PZTN with two and four NBD units, respectively. Upon visible-light excitation, energy transfer to the triplet state of NBD occurred, followed by NBD → quadricyclane (QC) conversion, which can be monitored by changes in steady-state or time-resolved spectra.

Comment on "Metal-Free Triplet Phosphors with High Emission Efficiency and High Tunability".

A series of β-hydroxy-vinylimine boron compounds 1-7 have been reported to exhibit unique dual emission, consisting of fluorescence and room temperature phosphorescence (RTP) in solution. This finding triggered intensive research of RTP in β-hydroxy-vinylimine boron derivatives. Herein, we show clear evidence that the associated dual emission, especially RTP, is caused by the experimental artifact, where bright emission intensity saturates the detection dynamic range of the fluorimeter.

Rational Tuning of Bis-Tridentate Ir(III) Phosphors to Deep-Blue with High Efficiency and Sub-microsecond Lifetime.

A new class of bis-tridentate Ir(III) complexes () was synthesized using carbene pincer pro-chelates PC1·H(PF) or PC2·H(PF) with either imidazolylidene or imidazo[4,5-]pyridin-2-ylidene appendages, together with a second cyclometalating 2,6-diaryoxypyridine chelate, L1H and L2H, differed by a NMe donor at the central pyridinyl fragment. The respective emission tuning between the ultraviolet and blue region was rationalized using time-dependent density functional theory (TD-DFT) approaches. Next, a highly efficient blue emitter () was synthesized by concomitant addition of two methyl groups and a single CF substituent at the central phenyl and peripheral imidazo[4,5-]pyridin-2-ylidene entities of the carbene pincer chelate, respectively.