Thanomngam, Pitiporn
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Preferred name
Thanomngam, Pitiporn
Alternative Name
Thanomngam, P.
Thanomngam, Pittiporn
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Email
pitiporn.th@kmitl.ac.th
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Item type:Publication, Band gap prediction of the alloying halide perovskites using GW compare to DFT-1/2 method(2020-10-26); The outstanding optoelectronic properties of methylammonium halide perovskites, including the tunable spectral absorption range, high carrier mobilities and low carrier recombination rates, make these materials are interesting for a decade year. In my works, a first-principle calculation based on non-local van der Waals-corrected Density Functional Theory (vdW-DFT) is performed to investigate high accuracy atomic structures and their properties of the alloying halide perovskites (CH3NH3PbIxBr1-x). While DFT generally underestimates the band gap for practically semiconductors and insulators, it provided a surprising accurate value for methylammonium halide perovskites. Unfortunately, this performance is not existing to another hybrid halide perovskite. The relativistic GW approximation is known to be a better-provided band gap more accurately, but at an extremely high computational cost were applied to the study. Here we also report the efficiency and accuracy of the bandgap calculations of methylammonium halide perovskites by using the self-consistent quasiparticle GW method (scGW) incorporated with the spin-orbit coupling comparing to recent develops DFT-1/2 method. The latter computational scheme provides accurate band gaps with the precision of the scGW method with no more computational cost than standard DFT. This method can solve the band gap problem by correcting the half-hole/half-electron occupation in the pseudopotentials. This work yields the possibility of the band gap prediction of alloying halide perovskite material (CH3NH3PbIxBr1-x) that good for optoelectronic design such as planar dye solar cell. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Pressure Dependence of Structural and Elastic Properties of Na2O: First-Principles Calculations(2022-01-01); The effect of high pressures, up to 40 GPa, on the structural and elastic properties of sodium oxide in cubic structure (c-Na<inf>2</inf>O) were investigated by first-principles calculations. The generalized gradient approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) functional was employed in the calculations. The calculated structural and elastic properties at zero pressure are consistent with the available results. The pressure dependence of structural and elastic properties was presented and discussed in detail. Under pressure, the elastic constants satisfy the Born criteria, indicating that c-Na<inf>2</inf>O is mechanically stable. Moreover, other elastic properties such as bulk modulus (B), shear modulus (G), and Young's modulus (E) under pressures were analyzed. Furthermore, the B/G values tend to increase with the increasing pressure, which means that pressure can improve the ductility of c-Na<inf>2</inf>O. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of pressure on structural and elastic properties of SnSe: First-principles calculations(2022-02-01); ; Limpijumnong, SukitSelected structural and elastic properties of an orthorhombic SnSe at an ambient pressure and under high pressures were investigated using first-principles calculations. At ambient pressure, the calculated structural parameters and elastic constants show a good agreement with previously reported values. Effects of pressure on structural and elastic properties were presented and discussed in detail. Moreover, the pressure dependence of selected structural and elastic properties, which relate to phase transition from an orthorhombic phase to the high-pressure phase, was analyzed. We suggested that the phase transition is related to the compression along the c- and b-axis which correspond to C<inf>33</inf> and C<inf>22,</inf> respectively.