Papers by Anusit Thongnum
Photoexcited charge-carrier transport in monolayer and bulk bismuth oxyiodide:the impact of the polaronic effect and deep-level defects
Physica scripta, Jun 25, 2024
Journal of Physics D-applied Physics, 2009
The in-plane transport of a two-dimensional hole gas in narrow Si/Si 1−x Ge x quantum wells (QWs)... more The in-plane transport of a two-dimensional hole gas in narrow Si/Si 1−x Ge x quantum wells (QWs) with the interface roughness effect was investigated using path-integral theory. The random variation of the well width causes the fluctuation potential in the in-plane direction. This fluctuation was integrated into the path integral via the eigenvalue model of the infinite barrier height QW. The hole mobility and the density of states can be derived in an analytic form. The calculated hole mobility was compared with the experimental data and a different theoretical approach based on the wavefunction model. We found that = 0.2 nm and = 4.5 nm give a good description of the experimental data. Our theory predicted the existence of the localized states, which reduces the hole mobility in addition to the prediction from the wavefunction method.
Polaron transport in hybrid CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> perovskite thin films
Nanoscale, 2020
Description of electron mobilities in epitaxial lanthanum-doped barium stannate films: Influences of LO phonons, threading dislocation, and ionized donor defects
Journal of Applied Physics
Lanthanum-doped barium stannate (La-doped BaSnO3 or LBSO) has attracted the attention of research... more Lanthanum-doped barium stannate (La-doped BaSnO3 or LBSO) has attracted the attention of researchers and engineers because of its wide range of potential applications in electronic and optoelectronic devices. This is due to a combination of its exceptional room temperature (RT) mobility of 320 cm2 V−1 s−1 and high visible range transparency. However, epitaxial LBSO films made using strategic deposition techniques such as molecular beam epitaxy, pulsed laser deposition, and magnetron sputtering show comparatively low RT mobilities, between 24 and 183 cm2 V−1 s−1, and an accurate description of these RT mobilities is still sought. Herein, we provide the underlying scattering mechanisms related to longitudinal optical (LO) phonons, threading dislocation, and ionized donor defects to elucidate the RT mobilities in LBSO epitaxial films. It was found that the total mobility estimated using Matthiessen's rule provided strong quantitative agreement with experimental results. The large p...
Effect of GeI2 and GeBr2 incorporation on perovskite properties and performance of carbon-based perovskite solar cells
Journal of the Korean Physical Society
Carrier Transport Dynamics in Lead-Free Double Perovskite Cs2agbibr6 Single Crystals
SSRN Electronic Journal
Heliyon
Sulfur-containing compounds are considered as attractive pharmacophores for discovery of new drug... more Sulfur-containing compounds are considered as attractive pharmacophores for discovery of new drugs regarding their versatile properties to interact with various biological targets. Quantitative structure-activity relationship (QSAR) modeling is one of well-recognized in silico tools for successful drug discovery. In this work, a set of 38 sulfur-containing derivatives (Types I-VI) were evaluated for their in vitro anticancer activities against 6 cancer cell lines. In vitro findings indicated that compound 13 was the most potent cytotoxic agent toward HuCCA-1 cell line (IC 50 ¼ 14.47 μM). Compound 14 exhibited the most potent activities against 3 investigated cell lines (i.e., HepG2, A549, and MDA-MB-231: IC 50 range ¼ 1.50-16.67 μM). Compound 10 showed the best activity for MOLT-3 (IC 50 ¼ 1.20 μM) whereas compound 22 was noted for T47D (IC 50 ¼ 7.10 μM). Subsequently, six QSAR models were built using multiple linear regression (MLR) algorithm. All constructed QSAR models provided reliable predictive performance (training sets: R tr range ¼ 0.8301-0.9636 and RMSE tr ¼ 0.0666-0.2680; leaveone-out cross validation sets: R CV range ¼ 0.7628-0.9290 and RMSE CV ¼ 0.0926-0.3188). From QSAR modeling, chemical properties such as mass, polarizability, electronegativity, van der Waals volume, octanolwater partition coefficient, as well as frequency/presence of C-N, F-F, and N-N bonds in the molecule are essential key predictors for anticancer activities of the compounds. In summary, a series of promising fluorothiourea derivatives (10, 13, 14, 22) were suggested as potential molecules for future development as anticancer agents. Key structure-activity knowledge obtained from the QSAR modeling was suggested to be advantageous for suggesting the effective rational design of the related sulfur-containing anticancer compounds with improved bioactivities and properties.
Discovery of Anilino-1,4-naphthoquinones as Potent EGFR Tyrosine Kinase Inhibitors: Synthesis, Biological Evaluation, and Comprehensive Molecular Modeling
ACS Omega
Influence of SCN− moiety on CH3NH3PbI3 perovskite film properties and the performance of carbon-based hole-transport-layer-free perovskite solar cells
Journal of Materials Science: Materials in Electronics, 2022
CH3NH3PbI3 perovskite films were prepared via a hot-casting method using six different CH3NH3I, P... more CH3NH3PbI3 perovskite films were prepared via a hot-casting method using six different CH3NH3I, PbI2 and Pb(SCN)2 solutions. Surface morphology of perovskite films with low SCN− dopant levels (0.0625 M and 0.125 M Pb(SCN)2) showed smooth surfaces and large grain sizes. However, with the high SCN− dopant levels (0.1875 M and 0.25 M Pb(SCN)2), rough surfaces were produced with pinholes. The crystal of pure CH3NH3PbI3 (0 M Pb(SCN)2) film is a tetragonal perovskite structure. XRD spectra of all five Pb(SCN)2 added films show the present of CH3NH3PbI3 films and the additional peak at 12.66°. Rietveld refinement analysis reveals that the Pb(SCN)2 addition causes the second phase PbI2 formation along with the tetragonal MAPbI3 perovskite film rather than the CH3NH3Pb(SCN)xI3-x perovskite formation. The carbon-based hole-transport-layer (HTL)-free perovskite (from 0.0625 M Pb(SCN)2 dopant) solar cell is the optimal ratio in generating a promising cell efficiency, 6.34%, with a good efficiency retention of 79.43% after 30 days of testing in comparison to a pure CH3NH3PbI3 (0 M Pb(SCN)2 dopant) perovskite solar cell with an efficiency retention of only 26.92%. The great stability of the Pb(SCN)2 added perovskite solar cells is attributed to the PbI2 layer covered MAPbI3 grains blocking oxygen and/or water molecules from degrading MAPbI3 perovskite.
Impact of the polar optical phonon and alloy scattering on the charge-carrier mobilities of FA0.83Cs0.17Pb(I1-xBrx)3 hybrid perovskites
Physical Chemistry Chemical Physics, 2021
Lead mixed-halide perovskites are promising absorption materials that are suitable for applicatio... more Lead mixed-halide perovskites are promising absorption materials that are suitable for applications in tandem solar cells using existing silicon technology. Charge-carrier mobility is an important factor that affects the performance...
ACS Omega, 2021
A library of 44 indole-sulfonamide derivatives (1− 44) were investigated for their cytotoxic acti... more A library of 44 indole-sulfonamide derivatives (1− 44) were investigated for their cytotoxic activities against four cancer cell lines (i.e., HuCCA-1, HepG2, A549, and MOLT-3) and antimalarial effect. Most of the studied indoles exhibit anticancer activity against the MOLT-3 cell line, whereas only hydroxylcontaining bisindoles displayed anticancer activities against the other tested cancer cells as well as antimalarial effect. The most promising anticancer compounds were noted to be CF 3 , Cl, and NO 2 derivatives of hydroxyl-bearing bisindoles (30, 31, and 36), while the most promising antimalarial compound was an OCH 3 derivative of non-hydroxyl-containing bisindole 11. Five quantitative structure−activity relationship (QSAR) models were successfully constructed, providing acceptable predictive performance (training set: R = 0.6186−0.9488, RMSE = 0.0938−0.2432; validation set: R = 0.4242−0.9252, RMSE = 0.1100−0.2785). QSAR modeling revealed that mass, charge, polarizability, van der Waals volume, and electronegativity are key properties governing activities of the compounds. QSAR models were further applied to guide the rational design of an additional set of 22 compounds (P1−P22) in which their activities were predicted. The prediction revealed a set of promising virtually constructed compounds (P1, P3, P9, P10, and P16) for further synthesis and development as anticancer and antimalarial agents. Molecular docking was also performed to reveal possible modes of bindings and interactions between the studied compounds and target proteins. Taken together, insightful structure−activity relationship information obtained herein would be beneficial for future screening, design, and structural optimization of the related compounds.
Transport properties of nonpolar CaZrO3/SrTiO3 heterointerfaces from scattering analysis
Journal of Physics D: Applied Physics, 2018
Temperature dependent electron mobility data from nonpolar CaZrO3/SrTiO3 heterostructures were an... more Temperature dependent electron mobility data from nonpolar CaZrO3/SrTiO3 heterostructures were analyzed and modeled considering various electron scattering mechanisms. We found that the total mobility based on Matthiessen's rule provided good quantitative agreement with experimental data over a wide temperature range (T = 2–295 K). Low-temperature mobility was limited by background impurities and interface roughness scatterings. A crossover between background impurity scattering and interfacial roughness scattering was observed with increasing carrier density. At temperatures of 10 < T < 150, electron–electron scattering was the main scattering mechanism, while at room temperature, electron–electron and polaron-LO phonon scatterings were dominant.
Exact two-dimensional propagator of an electron in magnetic and electric fields with a quadratic random potential
Electron transport properties inm-plane andc-plane AlN/GaN heterostructures with interface roughness and anisotropic in-plane strain scatterings
Journal of Physics D: Applied Physics, 2015
ABSTRACT Anisotropic transport properties of a two-dimensional electron gas in nonpolar m-plane A... more ABSTRACT Anisotropic transport properties of a two-dimensional electron gas in nonpolar m-plane AlN/GaN heterostructures with the interface roughness coupled anisotropic in-plane strain scattering were investigated theoretically using a path-integral framework. The scattering potential was composed of the interface roughness and the effective field from the electron charge and the net piezoelectric polarization. We showed that the anisotropic biaxial strains generate only the net piezoelectric polarization along the [0 0 0 1]-direction and cause anisotropy in electron mobility with a magnitude lower than the [1120] -direction. We also showed that the anisotropy in electron mobility reduced with increasing electron density. Moreover, the anisotropic electron mobility disappeared when the anisotropic in-plane strain scattering was removed, and the relation for pure interface roughness scattering was reestablished. This formulation with existing roughness parameters gave a good description for the experimental results of polar c-plane AlN/GaN heterostructures.
Interface roughness effect on density of states and mobility of narrow Si/Si1−xGexquantum wells: path-integral approach
Journal of Physics D: Applied Physics, 2009
The in-plane transport of a two-dimensional hole gas in narrow Si/Si1?xGex quantum wells (QWs) wi... more The in-plane transport of a two-dimensional hole gas in narrow Si/Si1?xGex quantum wells (QWs) with the interface roughness effect was investigated using path-integral theory. The random variation of the well width causes the fluctuation potential in the in-plane direction. This fluctuation was integrated into the path integral via the eigenvalue model of the infinite barrier height QW. The hole mobility and the density of states can be derived in an analytic form. The calculated hole mobility was compared with the experimental data and a different theoretical approach based on the wavefunction model. We found that ? = 0.2?nm and ? = 4.5?nm give a good description of the experimental data. Our theory predicted the existence of the localized states, which reduces the hole mobility in addition to the prediction from the wavefunction method.
Nanoscale, 2020
A comprehensive study of the transport properties of a prototypical CH3NH3PbI3 thin film is prese... more A comprehensive study of the transport properties of a prototypical CH3NH3PbI3 thin film is presented.
Solid State Communications, 2008
We calculate the density of states of a 2D electron gas in finite barrier height quantum wells wi... more We calculate the density of states of a 2D electron gas in finite barrier height quantum wells with the explicit inclusion of the interface roughness effect. By using Feynman path-integral method, the analytic expression is derived. The results show that the 2D density of states is dependent on the RMS of the fluctuation potential. The interface roughness causes localized states below the subband edge. We also apply the theory to model the finite barrier height quantum wells in Al x Ga 1−x As/GaAs. Published
Journal of Physics D: Applied Physics, 2011
Mobility of two-dimensional electron gases in MgZnO/ZnO heterostructures with interface roughness... more Mobility of two-dimensional electron gases in MgZnO/ZnO heterostructures with interface roughness effects was investigated theoretically using path-integral framework. We modelled the roughness-induced fluctuation by including two major effects, i.e. the electron and polarization-induced positive charge concentrations. We showed that both effects cause the scattering potential in the in-plane direction and hence affect the 2D mobility. In this work, we treated both electron and polarization-induced positive charge concentrations as equally important factors and then calculated the electron mobility and compared with the experimental result of Mg 0.2 Zn 0.8 O/ZnO heterostructure at high-electron concentrations. We found that the fitting parameters = 0.26 nm, = 2.5 nm gave good description to the mobility data. We also showed that neglecting the polarization-induced positive charge concentration led to overestimating the 2D mobility.
Description of low temperature bandtail states in two-dimensional semiconductors using path integral approach
Applied Physics Letters, 2013
We used the solutions from the variational path integral to suggest a function form of the bandta... more We used the solutions from the variational path integral to suggest a function form of the bandtail states of a two-dimensional system. The analytic solutions provide two regimes, i.e., the ground state (low temperature) and the semiclassical (high temperature) limits. We used the theoretical results to describe the results of the bandtail states in Si/SiO2 heterostructure reported recently (Jock et al., Appl. Phys. Lett. 100, 023503 (2012)). The low-temperature bandtail provided good agreement to the experimental results (sample B) with the parameters of D=0.225 nm, L=3.55 nm, and a=5nm.
Anisotropic transport properties of a two-dimensional electron gas in nonpolar m-plane AlN/GaN he... more Anisotropic transport properties of a two-dimensional electron gas in nonpolar m-plane AlN/GaN heterostructures with the interface roughness coupled anisotropic in-plane strain scattering were investigated theoretically using a path-integral framework. The scattering potential was composed of the interface roughness and the effective field from the electron charge and the net piezoelectric polarization. We showed that the anisotropic biaxial strains generate only the net piezoelectric polarization along the [0 0 0 1]-direction and cause anisotropy in electron mobility with a magnitude lower than the [1120] -direction. We also showed that the anisotropy in electron mobility reduced with increasing electron density. Moreover, the anisotropic electron mobility disappeared when the anisotropic in-plane strain scattering was removed, and the relation for pure interface roughness scattering was reestablished. This formulation with existing roughness parameters gave a good description for the experimental results of polar c-plane AlN/GaN heterostructures.
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Papers by Anusit Thongnum