The current investigation demonstrates highly efficient photochemical upconversion (UC) where a long-lived Zr(IV) ligand-to-metal charge transfer (LMCT) complex serves as a triplet photosensitizer in concert with well-estabilished 9,10-diphenylanthracene (DPA) along...

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Quantum−dot/molecule composites (QD/mol) have demonstrated useful photochemical properties for many photonic and optoelectronic applications; however, a comprehensive understanding of these materials remains elusive. This work introduces a series of cadmium(II) selenide/1-pyrenecarboxylic acid (CdSe/PCA) nanomaterials featuring bespoke PCA surface coverage on CdSe585 (coded by the peak of the first exciton absorption band) to glean insight into the QD/mol photophysical behavior. Tailoring the energy gap between the CdSe585 first exciton band (2.1 eV) and the lowest PCA triplet level (T 1 = 2.0 eV) to be nearly isoenergetic, strong thermally activated delayed photoluminescence (TADPL) is observed resulting from reverse triplet−triplet energy transfer. The resultant average decay time constant (τ obs ) of the photoluminescence emanating from CdSe585 is deterministically controlled with surface-bound PCA n chromophores (n = average number of adsorbed PCA molecules) by shifting the triplet excited state equilibrium from the CdSe585 to the PCA molecular triplet reservoir as a function of n.

A highly accurate and reliable screening method for enantiomeric excess of amine derivatives in the presence of water is reported. The fluorescence-based screening system has been realized by self-assembly of chiral diol-type dyes (BINOL, VANOL and VAPOL), 2-formylphenylboronic acid, and chiral amines forming iminoboronate esters. The structure and chirality of the amine analytes determine the stability of the diastereomeric iminoboronate esters, which in turn display differential fluorescence. The fluorescence signal reflects the enantiomeric purity of the chiral amines and was utilized in high-throughput arrays. The arrays were able to recognize enantiomeric excess of amines, amino esters, and amino alcohols. In addition to qualitative analysis, quantitative experiments were successfully performed. Studies of the role of additives such as water or citrate were carried out to gain insight into the stability of the iminoboronate esters. It is shown that the above additives destabilize less stable esters while the stable esters remain unchanged. Thus, the presence of water and citrate leads to increased difference between the diastereomeric iminoboronates and contributes to the enantiodiscrimination of the chiral amines.

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Increasing security needs require compact and portable detection tools for the rapid and reliable identification of explosives used in improvised explosive devices (IEDs). We report of an easy-to-use optical sensor for both vapour-phase and solution-phase identification of explosive mixtures that uses a cross-reactive fluorimetric sensor array comprising chemically responsive fluorimetric indicators composed of aromatic aldehydes and polyethyleneimine. Ammonium nitrate-nitromethane (ANNM) was analyzed by paper microzone arrays and nanofiber sensor mats. Progress toward wearable sensors based on electrospun nanofiber mats is outlined.

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Recognition of electroneutral Lewis bases and anions in aqueous media is extremely difficult. We show that fluorescent coordinatively unsaturated metal complexes can recognize various Lewis bases while providing an easy-to-detect fluorescence response. This approach is applied to the detection of adrafinil, a banned performance-enhancing drug.