Bismuth dopants have attracted intensive studies experimentally for their extremely broad near-infrared luminescence. Here we performed first-principles calculations to investigate the site occupancy and valence state by taking the condition of synthesis into consideration, and then calculated the excited states and various transitions of the bismuth ions by focusing on the targeted valent state Bi in a variety of ternary chloride MXCl (M = K, Rb, Cs; X = Mg, Cd) hosts. The results on formation energies and charge transition levels show that vacant defects play an important role in the charge compensation for the bismuth dopants, and a lower chemical potential of chlorine benefits the stabilization of Bi at monovalent M sites. The multi-configurational quantum-chemical method and the constrained occupancy approach together confirm the near-infrared photoluminescence of Bi, and the spontaneous emission rates due to electric-dipole and magnetic-dipole contributions are evaluated and analyzed in terms of transition selection rules, to affirm the Bi nature of the long lifetime luminescence. Our results show that the mechanisms revealed in this study, and the combination of density-functional calculations for defect formation energies with the wave-function based calculations for optical transitions, are effective in exploring the luminescence of bismuth dopants in solids.
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http://dx.doi.org/10.1039/d1cp01632f | DOI Listing |
Heliyon
April 2024
Materials Science Research Laboratory, Department of Electrical and Electronic Engineering, University of Dhaka, Dhaka-1000, Bangladesh.
Here we investigated the effects of Ce and Mo doping on hydrothermally synthesized bismuth vanadate BiVO nanoparticles (NPs). The existence of monoclinic scheelite and tetragonal zircon phases of NPs was validated from Rietveld refinement of the powdered X-ray diffraction, room temperature Raman, and Fourier-transform infrared spectroscopy. The co-doping of Bi and V sites with respective Ce and Mo dopants in a mixed tetragonal zircon and monoclinic scheelite phases of BiVO lattice was corroborated from high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy.
View Article and Find Full Text PDFMater Horiz
December 2024
MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, University of Auckland, Private Bag 92019, Auckland, New Zealand.
Liquid metal (LM) technologies are rapidly advancing in modern materials science, with low melting point metals playing a pivotal role in emerging applications. Recent studies reveal that doped liquid gallium systems form spectacular and diverse surface structures during cooling, [Tang , , 2021, , 431-439] sparking renewed interest in the possible geometric structuring at the surface of pure liquid gallium. Distinct from the known increase in surface density, this lateral surface order has long been hinted at experimentally and theoretically but has remained enigmatic.
View Article and Find Full Text PDFChemSusChem
November 2024
State Key Laboratory of Advanced Electromagnetic Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
Chlorine-rich lithium argyrodite is considered as a promising superionic conductor electrolyte, but its practical application is limited due to poor air stability and instability toward lithium metal. In this work, BiF is proposed as a multi-functional dopant for electrolyte modification, and the effects on the ionic conductivity, air stability, critical current density, and electrolyte/Li metal interfacial stability are studied. The results show that the doped electrolyte LiPBiSClF (LPBiSClF) still maintains a relatively high ionic conductivity of 5.
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October 2024
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
Thermoelectric (TE) generators based on bismuth telluride (BiTe) are recognized as a credible solution for low-grade heat harvesting. In this study, an combinative doping strategy of both the donor (Ag) and the acceptor (Ga) in AgGaTe as dopants is developed to modulate the microstructure and improve the value of p-type BiSbTe. Specifically, the distribution of Ag and Ga in the matrix synergistically introduces multiple phonon scattering centers including lath twins, triple junction boundaries, and Sb-rich nanoprecipitates, leading to an obviously suppressed lattice thermal conductivity of 0.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2024
Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Education University, Guiyang 550018, China.
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