The lead white pigment, composed of two main mineral phases cerussite PbCO and hydrocerussite 2PbCO·Pb(OH), has been used in paintings since the Antiquity. The study of historical sources revealed that a large variety of lead white qualities were proposed, depending on the degree of sophistication of the pigment synthesis. Investigation of photoluminescence of the two constitutive mineral phases gave insight into the origin of the visible emission of these materials and emphasized the influence of structural defects on their photoluminescence properties. These effects were observed by combining emission and excitation spectra in two-dimensional representations. For each excitation wavelength, between 250 and 400 nm (4.9-3.1 eV), luminescence spectra were collected between 400 and 800 nm (3.1-1.5 eV). Two types of emission-excitation bands were identified: an emission excited in the optical bandgap of the compounds (about 5 eV), which depends on the constitutive phase (2.8 eV in cerussite and 2.1 eV in hydrocerussite), and broad emission bands in the same energy range excited below the optical gap, which are sensitive to the synthesis method and the nature of postsynthesis treatments. It is proposed that this sensitivity of photoluminescence properties of lead-white pigments could be used as fingerprints of their origin and history.
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http://dx.doi.org/10.1021/acs.analchem.6b04195 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
School of Information Science and Technology, Fudan University, Shanghai 200433, China.
To date, various kinds of memristors have been proposed as artificial neurons and synapses for neuromorphic computing to overcome the so-called von Neumann bottleneck in conventional computing architectures. However, related working principles are mostly ascribed to randomly distributed conductive filaments or traps, which usually lead to high stochasticity and poor uniformity. In this work, a heterostructure with a two-dimensional WS monolayer and a ferroelectric PZT film were demonstrated for memristors and artificial synapses, triggered by in-plane ferroelectric polarization.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States.
The photophysical properties of six new luminescent tetrahedral Zn(II) complexes are presented that survey two electronic donor moieties (phenolate and carbazolate) and three electronic acceptors (pyridine, pyrimidine, and pyrazine). A unique ligand based on an -terphenyl motif forms an eight-membered chelate, which enhances through-space charge-transfer (CT) interactions by limiting through-bond conjugation between the donor and acceptor. A single isomeric product was obtained in yields up to 90%.
View Article and Find Full Text PDFChirality
January 2025
Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Narashino, Japan.
The synthesis, structure, and circularly polarized luminescence (CPL) properties of axially chiral boron difluoride complexes are described. A series of optically pure bis (boron difluoride) complexes were prepared in 5 steps from commercially available (S)- or (R)-BINOL as starting materials. The complexes were found to exhibit similar yellow photoluminescence in solution, regardless of the type of substituents on the nitrogen atoms.
View Article and Find Full Text PDFNanotechnology
January 2025
Experimentalphysik, Saarland University, Fachrichtung 7.2, Campus E2.6, 66123 Saarbruecken, Saarbrucken, Saarland, 66123, GERMANY.
Color centers are promising single-photon emitters owing to their operation at room temperature and high photostability. In particular, using nanodiamonds as a host material is of interest for sensing and metrology. Furthermore, being a solid-state system allows for incorporation to photonic systems to tune both the emission intensity and photoluminescence spectrum and therefore adapt the individual color center to desired properties.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Institute of Frontier Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Qingdao, 266237, P. R. China.
Metal halide perovskites and their derivatives are gaining significant attention as photoluminescent materials due to their exceptional light-emitting properties. However, most research has concentrated on electroluminescence and photoluminescence, there remains a substantial gap in the exploration of mechanoluminescence (ML) properties in perovskites, making this field largely uncharted. ML is an ancient and intriguing luminescent phenomenon that occurs when a material is subjected to mechanical forces.
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