Entries by Katy

Dihydroquinolylazotetrazole dyes: Effect of a substituent at the tetrazole fragment on spectral properties and thermal Z‒E isomerization in organic solvents

New hetarylazo dyes with dihydroquinoline and tetrazole moieties with different substituents at the tetrazole cycle were synthesized and their spectral properties and thermal Z‒E isomerization were investigated in toluene, MeCN and DMSO. The substitution of H with the CH3 group at the tetrazole fragment results in the disappearance of concentration dependence of the absorption spectra observed for the dyes with unsubstituted […]

Development of Dual-Frequency PMUT Arrays Based on Thin Ceramic PZT for Endoscopic Photoacoustic Imaging

This paper presents a dual-frequency piezoelectric micromachined ultrasonic transducer (pMUT) array based on thin ceramic PZT for endoscopic photoacoustic imaging (PAI) applications. With a chip size of 7×7 mm 2 , the pMUT array consists of 256 elements, half of which have a lower resonant frequency of 1.2 MHz and the other half have a higher resonant frequency of […]

Nanocomposite of Au and black phosphorus quantum dots as versatile probes for amphibious SERS spectroscopy, 3D photoacoustic imaging and cancer therapy

To expand the bioimaging applications of Au and black phosphorus, black phosphorus quantum dot-Au hybrids (Au-BPQD nanohybrids) are fabricated for multiple theranostic applications in this study. By simply varying the ratios of BPQDs and Au3+, the BPQDs assisted Au3+ reduction outputs two kinds of nanohybrids with different functions. The less BPQDs lead to small size Au-BPQD nanohybrids […]

Facile Multistep Synthesis of ZnO-Coated β-NaYF4:Yb/Tm Upconversion Nanoparticles as an Antimicrobial Photodynamic Therapy for Persistent Staphylococcus aureus Small Colony Variants

Antibacterial treatment strategies using functional nanomaterials, such as photodynamic therapy, are urgently required to combat persistent Staphylococcus aureus small colony variant (SCV) bacteria. Using a stepwise approach involving thermolysis to form β-NaYF4:Yb/Tm upconversion nanoparticles (UCNPs) and surface ligand exchange with cetyltrimethylammonium bromide (CTAB), followed by zeolite imidazolate framework-8 (ZIF-8) coating and conversion to zinc oxide (ZnO), β-NaYF4:Yb/Tm@ZnO nanoparticles […]

Photophysics of Ru(II) complexes with hydroxylated diimine ligands: Photoinduced electron/proton transfer to anthraquinone

This manuscript reports the reaction of the 3MLCT excited states of two luminescent chromophores, [(bpy)2Ru(OHbpy)]2+ and [(bpy)2Ru(OMebpy)]2+ (bpy = 2,2′-bipyridine, OHbpy = 4-hydroxy-2,2′-bipyridine, OMebpy = 4-methoxy-2,2′-bipyridine), with anthraquinone (AQ). A series of luminescence, electrochemical, spectrophotometric and transient absorption studies were done in order to determine free energies for the potential reaction paths between the photoexcited complexes and AQ. For the OMebpy complex, only excited state electron transfer (ET*) […]

TIPS-pentacene triplet exciton generation on PbS quantum dots results from indirect sensitization

Many fundamental questions remain in the elucidation of energy migration mechanisms across the interface between semiconductor nanomaterials and molecular chromophores. The present transient absorption study focuses on PbS quantum dots (QDs) of variable size and band-edge exciton energy (ranging from 1.15 to 1.54 eV) post-synthetically modified with a carboxylic acid-functionalized TIPS-pentacene derivative (TPn) serving as […]

UV photobleaching of carbon nanodots investigated by in situ optical methods

Carbon dots are a family of optically-active nanoparticles displaying a combination of useful properties that make them attractive for many applications in photonics and photochemistry. Despite the initial claims of high photostability of carbon dots even under prolonged illuminations, several recent studies have evidenced their photobleaching (PB) under UV light, detrimental for some applications. A […]

Coordination engineering of Cu-Zn-Sn-S aqueous precursor for efficient kesterite solar cells

Aqueous precursors provide an alluring approach for low-cost and environmentally friendly production of earth-abundant Cu2ZnSn(S, Se)4 (CZTSSe) solar cells. The key is to find an appropriate molecular agent to prepare a stable solution and optimize the coordination structure to facilitate the subsequent crystallization process. Herein, we introduce thioglycolic acid (TGA), which possesses strong coordination (SH) and […]

Synthesis and Photostability of Cyclooctatetraene-Substituted Free Base Porphyrins

A series of free base meso-tetraarylporphyrins functionalized with substituents containing one, two, and four cyclooctatetraene (COT) moieties have been obtained and characterized by spectral and photophysical studies. Three COT-free porphyrins served as reference compounds. COT is a triplet quencher, well-known to enhance the photostability of several, but not all, fluorophores. In the case of porphyrins, substitution […]

Structure of a Zinc Porphyrin-Substituted Bacterioferritin and Photophysical Properties of Iron Reduction

The iron storage protein bacterioferritin (Bfr) binds up to 12 hemes b at specific sites in its protein shell. The heme b can be substituted with the photosensitizer Zn(II)-protoporphyrin IX (ZnPP), and photosensitized reductive iron release from the ferric oxyhydroxide {[FeO(OH)]n} core inside the ZnPP-Bfr protein shell was demonstrated [Cioloboc, D., et al. (2018) Biomacromolecules19, 178–187]. This report describes the […]