arXiv subjects

A. Laref

Publications and source records attributed to A. Laref.

10 recordsLinked to original sources

arXiv2026

Performance Analysis of Double Perovskite-Based Solar Cells Using SCAPS-1D Simulation: A brief review

Lead-free double perovskites are among the rapidly developing next-generation solar cell technologies, providing the required low toxicity, stability, as well as high optoelectronic potential. So far, experimentally prepared lead-free perovskite solar cell devices are reported to have low power conversion efficiency (PCE) for practical application as compared to the lead-based perovskites. In recent years, numerical simulations have emerged as a cost-effective approach that plays a crucial role in expediting scientific research, can bridge the gap between experiment and theory, and provide predictive information regarding the preparation of solar cells and their PCEs without undergoing real-time experiments. The tools, such as 1D numerical simulation software SCAPS-1D, are now needed to test newer architectures and determine what exactly is holding them back. So far in the field of solar cell research, SCAPS-1D has been extensively used and looks like a powerful software due to its user-friendliness and simulation of results in a few seconds. The speed and ease of simulation make SCAPS-1D a very popular tool; as a result, it enables rapid optimization of a large number of photovoltaic devices and their performances without undergoing any experimental work, which can save time and money. However, one serious drawback is that the SCAPS-1D simulator works only for 1D configurations. It is ineffective in incorporating atomistic interactions and 3D effects. Hence, the efficacy of the SCAPS-1D simulator solely relies on the accuracy of the input parameters that the user provides, failing which may give wrong results and large deviations from accuracy.

cond-mat.mtrl-sci↗

arXiv2026

A DFT and Machine Learning-Assisted Study on the Lattice Thermal Conductivity of LiCdSb for Thermoelectric Applications

By using first-principles density functional theory (DFT) and the Boltzmann transport equation, we have calculated the corresponding electronic and thermoelectric properties of LiCdSb. For calculating electron transport properties, accurate band-structure estimation is crucial. Hence, for the precise band gap calculation, we have implemented a hybrid functional HSE06, which is widely known for its high accuracy. To evaluate the thermoelectric performance of a material, the calculation of lattice thermal conductivity (Kl) is a key parameter. However, from a theoretical perspective, the calculation of lattice thermal conductivity is very complex and demands huge computational resources. Therefore, in this work, we have opted for an alternative method of machine-learning interatomic potentials (MLIPs) for the calculation of Kl. Our result of Kl=0.24 Wm^-1K^-1 at room temperature is in qualitative agreement with the available theoretical and experimental data. The figure of merit (ZT) with Kl estimated from Slack+TDEC ZT is 0.18 at 300 K, and machine learning (ML) models ZT is 0.17 at 300K, combining with HSE06-based electronic transport properties agreed well with the available experimentally reported value of ZT is 0.10 at 300K. However, we report the ZT value well above the benchmark value of 1 beyond 600K. The ZT value exceeding 1 at higher temperatures makes LiCdSb a promising material for high-temperature energy conversion.

cond-mat.mtrl-sci↗

arXiv2026

Tailoring the Optoelectronic, Photocatalytic, Thermoelectric and Thermodynamic Properties of Halides Li2InBiX6 (X = Cl, Br, I) for Energy Conversion: A DFT Study

Double perovskite halides are emerging as promising materials for a wide range of applications, particularly in renewable energy technologies such as solar cell devices, thereby contributing to addressing global energy demands. In this work, the structural, electronic, optical, dielectric, thermoelectric, and photocatalytic properties of Li2InBiX6 (X = Cl, Br, I) halides are systematically investigated using density functional theory. The calculated formation energies confirm the thermodynamic stability of these compounds in the cubic phase. The studied materials exhibit semiconducting behavior with direct bandgaps of 1.7 eV, 1.3 eV, and 1.1 eV for Li2InBiCl6, Li2InBiBr6, and Li2InBiI6, respectively. The complex dielectric function is analyzed to explore their optical response, revealing strong absorption in the infrared and visible regions, indicating suitability for optoelectronic applications. Thermoelectric properties, including the Seebeck coefficient, electrical conductivity, and figure of merit (ZT), are evaluated over a temperature range of 30 to 800 K. The relatively small bandgaps contribute to enhanced thermoelectric performance, reflected in improved power factors. Furthermore, photocatalytic analysis indicates that Li2InBiX6 compounds are suitable candidates for water oxidation reactions within the pH range of 0 to 7. Overall, the combined thermoelectric and optical performance highlights these double perovskite halides as promising materials for future energy conversion applications.

cond-mat.mtrl-sci↗

arXiv2025

Interfacial effect on the optoelectronic and piezoelectric properties of Ge-Sn terminated Halide Perovskite heterostructure from first-principles study

Since the very early stages of research on sustainable technologies, green energy conversion has always been a prime focus. With the discoveries of countless functional materials in recent years, significant progress has been made to meet the global energy demand for sustainable development. Among them, halide perovskites have emerged as one of the most promising and reliable materials. In this work, we have investigated the lead-free halide perovskites, vis CsGeCl3 and RbSnBr3, within a framework of density functional theory (DFT) to explore their potential applicability in harvesting clean and renewable energy. This study gives a comprehensive analysis of the bulk, surface (001), and Ge-Sn-terminated interfaces within GGA and mGGA functionals. Interestingly, the inherent asymmetric arrangements of the systems exhibit remarkable optoelectronic and piezoelectric properties. The piezoelectric performance of each surface cut has been validated through the electromechanical coupling calculation.

cond-mat.mtrl-sci↗

arXiv2025

A comprehensive first principles investigation of A$_2$BH$_6$ type (A= Li,Na, and K; B= Al, and Si) double perovskite hydrides for high capacity hydrogen storage

Recent breakthroughs in vacancy-ordered double perovskite hydride materials have underscored their significant potential for integration into next-generation high-capacity hydrogen energy storage systems. We perform extensive first principles calculations leveraging both the GGA and hybrid-HSE06 functionals to systematically explore the intrinsic properties of A$_2$BH$_6$ complex hydrides. Thermodynamic stability for each hydride is demonstrated and confirmed by negative formation energies, determined by both the GGA and HSE06 formalisms. Additionally, mechanical stability is validated through compliance with Born's stability criteria. Electronic properties analysis reveals a semiconducting behavior in Si based hydrides (A2SiH6 ), whereas Al based (A$_2$AlH$_6$) display metallic nature, regardless of the A site atoms and functionals adopted. For the semiconducting hydrides, we have observed higher optical absorption peak greater than 106 (1/cm) in the UV regime indicating potential application in UV-optoelectronic devices. Furthermore, all studied compounds adhere to Debye's low-temperature specific heat behavior and converge to the classical Dulong-Petit limit at elevated temperatures, in accordance with fundamental thermodynamic principles. For hydrogen storage applications, both Al- and Si-based hydrides. meet key benchmarks set by the U.S. Department of Energy (DOE), achieving gravimetric hydrogen capacities (C$_{wt}$) exceeding 5.5 percent when A = Li or Na, and exhibiting volumetric hydrogen densities greater than 40 g.H2/L. Among all studied hydrides, Li$_2$AlH$_6$ and Li$_2$SiH$_6$ emerge as the two most promising candidates due to their outstanding Cwt greater than 12.0 percent , elevated density greater than 140 g.H$_2$/L, and favorable hydrogen desorption temperature ranges TD = 450 to 650 K.

cond-mat.mtrl-sci↗

arXiv2025

Group-I lead oxide X$_2$PbO$_3$ (X=Li, Na, K, Rb, and Cs) glass-like materials for energy applications: A hybrid-DFT study

Pb-based compounds have garnered considerable theoretical and experimental attention due to their promising potential in energy-related applications. In this study, we explore the glass-like alkali metal lead oxides X$_2$PbO$_3$ (X=Li, Na, K, Rb, Cs) and assess their suitability for piezoelectric and thermoelectric applications. First-principles calculations were performed using hybrid density functional theory (DFT), incorporating B3LYP, HSE06, and PBE0 functionals. Among these, PBE0 is identified as the most accurate, yielding lattice parameters in close agreement with experimental data. Structural stability was confirmed through evaluation of thermal, mechanical, and formation energies. For the non-centrosymmetric orthorhombic phase Cmc2$_1$-X$_2$PbO$_3$ (X=K, Rb, Cs), piezoelectric constants were computed via both the numerical Berry phase (BP) method and the analytical Coupled Perturbed Hartree-Fock/Kohn-Sham (CPHF/KS) formalism. Notably, Cs$_2$PbO$_3$ exhibited a piezoelectric coefficient of e$_{33}$ = 0.60 C m$^{-2}$ (CPHF/KS), while K$_2$PbO$_3$ showed e$_{32}$ = -0.51 C m$^{-2}$ (BP). Thermoelectric properties were investigated using the semiclassical Boltzmann transport theory within the rigid band approximation. The calculated thermoelectric performance reveals promising figures of merit (ZT), ranging from 0.3 to 0.63, suggesting these materials are applicable as future thermoelectric materials.

cond-mat.mtrl-sci↗

arXiv2025

The study of electronic, structural, mechanical, and piezoelectric properties of bulk NbOX2 (X = Cl, Br, and I) using density functional theory

In this work, we have performed a comprehensive study of dielectric materials NbOX2 (X=Cl, Br, and I) within the framework of density functional theory, incorporating both conventional and hybrid functionals.Our studies focus on the structure, electronic, elastic, and piezoelectric properties. Piezoelectricity is an innovative avenue to extract energy by manipulating the material's structures via mechanical stress. The use of non-lead-based material for piezoelectricity added an advantage of a greener approach. Among the investigated materials, bulk NbOI2 exhibits the highest piezoelectric response of 6.32 C/m$^2$, which is around 31% higher than NbOCl2, NbOBr2 and even lead zirconate titanate.

cond-mat.mtrl-sci↗

arXiv2025

2D MXene-Based Photocatalysts for Efficient Water Splitting and Hydrogen Evolution: A brief review

Photocatalytic water splitting offers a viable and sustainable method for hydrogen production. MXenes, a class of 2D transition-metal carbides/nitrides, have emerged as potential photocatalysts and co-catalysts due to their tunable electronic properties, high conductivity, and surface functionality. This review explores recent advances in MXene-based photocatalysts for hydrogen production, discussing their synthesis, electronic structures, and photocatalytic mechanisms. The key challenges, including stability issues, charge recombination, and bandgap optimisation, are critically analysed. Finally, future research directions are outlined to improve MXene-based systems for large-scale hydrogen production.

cond-mat.mtrl-sci↗

arXiv2024

Recent progress on the solid-state materials for photocatalysis

Hydrogen is considered an alternative source of energy to fossil fuels for the fulfilment of current energy demands. Photocatalysis initiates the hydrogen evolution reaction which is believed to be the greenest approach to produce hydrogen through clean, safe, and environmentally friendly methods. In this Review, we focus mainly on the comprehensive analysis of the 2D and 3D bulk materials on the basis of their superior photocatalytic activities. However, several literatures have reported the superiority of 2D material over the bulk counterpart in terms of photocatalytic performance owing to their ultrathin layered structures, offer a higher surface-to-volume ratio, flexibility, large active sites for incoming H2O molecules, etc. We have thoroughly analysed the drawbacks of various hydrogen production methods focusing on the photocatalysis mechanism and the processes of evolution of hydrogen. In addition to this, a short overview of the various solid-state materials for photocatalysis that have been developed so far and their mechanisms are discussed. Lastly, we have discussed the recent developments in 2D materials and their composites as promising photocatalysts.

cond-mat.mtrl-sci↗

arXiv2020

Induced Ferromagnetism in bilayer Hexagonal Boron Nitride (h-BN) on vacancy defects at B and N sites

We investigated the electronic and optical properties of bilayer AB stacked Boron and Nitrogen vacancies in hexagonal Boron Nitride (h-BN) using density functional theory (DFT). The density of states (DOS) and electronic band structure showed that Boron vacancy in bilayer h-BN results in a magnetic and conducting ground state. The band gap energy ranges from 4.56 eV for the pristine BN bilayer to 0.12 eV for a single Nitrogen vacancy in the bilayer. Considering the presence of 1,3,4-Boron vacancy, half metallic character is observed. However, the 2-boron vacancy configuration resulted in metallic character. The bilayers with 1,2,3,4- Nitrogen vacancy has a band gap of 0.39, 0.33, 0.28 and 0.12eV respectively, which is significantly less than the pristine band gap. Also B and N vacancy induces ferromagnetism in the h-BN bilayer. The maximum total magnetic moment for the Boron vacant system is 6.583uB in case of 4-Boron vacancy configuration. In case of Nitrogen vacancy system it is 3.926uB for 4-Nitrogen vacancy configuration. The optical response of the system is presented in terms of the absorption coefficient, refractive index and dielectric constant for pristine as well as the defective configurations. Negative value of dielectric constant for Boron vacant system in the energy range 0.9-1.4 eV and for Nitrogen vacant system in the energy range 0.5-0.8 eV opens an opportunity for it to be utilized for negative index optical materials. The current study shows that B and N vacancies in bilayer h-BN could have potential applications in nano-structure based electronics, optoelectronics and spintronic devices.

cond-mat.mtrl-sci↗