Optical and electronic properties of niobium oxynitrides with various N/O ratios: insights from first-principles calculations

Band Structure Engineering and Optical Properties of Pristine and Doped Monoclinic Zirconia (m-ZrO2): Density Functional Theory Theoretical Prospective

“…Despite many computational methods to inspect the electronic populations and charges of atomic systems, it is commonly accepted that the absolute magnitude of the atomic charges has little physical meaning because of the extreme sensitivity to the atomic basis, but the relative values are still helpful to study some physical properties of pure and doped crystal systems. ,, In this report, we analyzed Mulliken population analysis to compare electronic charges and to inspect charge transfer. Table displays the numerical data of Mulliken charges and band gaps of pristine and doped systems.…”

“…The imaginary part ε 2 (W) could be calculated using the momentum matrix element and is given by the following expression: − where e is the electronic charge, Ω is the volume of the unit cell, φ is the light frequency, ȗ is the vector defining the polarization of the incident field, and φ k c and φ k v are the wave functions of conduction and valence bands at k , respectively. Using the Kramers–Kronig relation, ,,,, one can derive the real part ε 1 (W). Other optical properties such as the absorption spectrum α­(W), the imaginary part of the refractive index n (W), and the imaginary part of the refractive index k (W) can be derived from ε 1 (W) and ε 2 (W), as given by eqs −. …”

“…14 Despite many computational methods to inspect the electronic populations and charges of atomic systems, it is commonly accepted that the absolute magnitude of the atomic charges has little physical meaning because of the extreme sensitivity to the atomic basis, but the relative values are still helpful to study some physical properties of pure and doped crystal systems. 5,7,9 In this report, we analyzed Mulliken population analysis 42 to compare electronic charges and to inspect charge transfer. Table 1 2) the charge transfer from metal to O decreases in the order W, Nb, and Zr, which may be due to the higher electronegativity of W (2.36) compared to Nb(1.6) and Zr(1.33), 5 (3) doping m-ZrO 2 and similar metal oxides with 4d and 5d metals like Nb and W may be very helpful in tuning the electronic properties of these metal oxides, which could be excellent candidates for PEC systems.…”

“…Aircraft that cannot fly, factories and power stations that are closed, streets that are crowded with a huge number of vehicles that cannot be driven for even 1 km, and millions of people without jobs: this will be the situation of a world without energy. In order to avoid this scenario, scientists and researchers are working seriously toward finding new energy resources to decrease the dependence on fossil fuels. , Capturing solar energy and converting it into clean chemical energy by photoelectrochemical energy conversion (PEC) systems is considered a very promising route to overcome the shortage of nonrenewable energy globally. , In this context, researchers have made great effort to develop and discover new materials for this new technology. − Metal oxides are considered excellent candidates for this technology because of their good electrical and mechanical properties. , Furthermore, the wide band gap for metal oxides can be tailored by doping.…”

Photoelectrocatalytic hydrogen production on ternary Co‐Pi/Ag/TiON nanotube array photocatalysts

“…[12][13][14][15] Of particular interest is the ammonolysis of metal oxides to convert them into the corresponding oxynitrides that are optically active in the visible region of the light spectrum and were shown to activate the water splitting process. [16][17][18][19][20] Equally important is the use of localized surface plasmon resonance (LSPR) of metal nanoparticles that enables the strong coupling of visible light with charge carriers in the nanoparticles, thus facilitates the water splitting process. [21][22][23][24] On the other hand, cocatalysts have been used to improve the electrocatalytic performance of many photocatalysts used to split water.…”