Solar Energy and Sustainable Development Journal

DFT Analysis of Structural, Elastic and Optoelectronic Enhancements in LiGeCl₃ Under Pressure for Photovoltaic Applications

Mohammed Miri — 2026-04-04

This study focuses on the crystalline lithium-based perovskite material, LiGeCl₃, with a view to improving its structural, elastic, electronic and optical properties by exploiting the effect of hydrostatic pressure. Combining density of states (DOS and PDOS) analysis with DFT and GGA approximation results, it is shown that the application of pressure reduces the lattice parameter, enhancing self-cohesion and stabilising the atomic structure. At ambient pressure, LiGeCl₃ exhibits semiconducting properties with a direct band gap, dominated by the p-orbitals of Cl atoms in the valence band and Ge in the conduction band. Under increasing pressure (0 to 6 GPa), the band gap is progressively reduced until it disappears at 6 GPa, leading to an electronic transition from a semiconducting to a metallic state. This transition results from the compression of the crystal lattice, which intensifies orbital interactions and causes the valence and conduction bands to overlap. In addition, pressure significantly enhances the optoelectronic properties of LiGeCl₃, including absorption in the visible spectrum, spectral reflectivity and refractive index, making the material more suitable for photovoltaic applications. . These results highlight the potential of LiGeCl₃ in engineering advanced materials for semiconductor and optoelectronic devices, while demonstrating the crucial role of hydrostatic pressure as a tool for modulating material properties

Geometry-Dependent Thermal Transport in Porous Silicon: A Computational Study of Pore Geometry and Porosity Effects

Othman Soubai — 2026-04-04

تستعرض هذه الدراسة كيفية تأثير هندسة المسام والمسامية على التوصيل الحراري وخصائص نقل الحرارة في السيليكون المسامي، باستخدام أداة "أوبن بي تي إي"، وهي أداة حسابية مفتوحة المصدر تعتمد على معادلة بولتزمان للنقل. قمنا بدراسة ثلاث أشكال هندسية للمسام (دائرية، مستطيلة وسداسية) مع نسب مسامية من 5% إلى 45% لدراسة تأثيرها على النقل الحراري الذي يتم بواسطة الفونونات. أظهرت النتائج علاقة واضحة بين التوصيل الحراري وشكل المسام ونسبة المسامية، إذ سجلت المسام ذات الشكل المستطيل أعلى قيم للتوصيل الحراري التي تتراوح من 64.4 واط/(متر•كلفن) عند نسبة 5% من المسامية إلى 26.7 واط/(متر•كلفن) عند نسبة 45% من المسامية. بينما أعطت للمسام الدائرية قيما متوسطة للتوصيل الحراري، تتراوح من 56.8 واط/(متر•كلفن) عند نسبة 5% من المسامية إلى 9.5 واط/(متر•كلفن) عند نسبة 45% من المسامية. أما بالنسبة للمسام السداسية فقد حققت أدنى قيم للتوصيل الحراري، حيث تراوحت بين 54.6 واط/(متر•كلفن) عند نسبة 5% من المسامية إلى 7.2 واط/(متر•كلفن) عند نسبة 45% من المسامية.

Parametric study of the impact of insulation and wall thickness in straw-reinforced adobe structures on energy performance in a Moroccan desert climate: A case study of Errachidia city

Abdelmounaim Alioui — 2026-04-04

In hot and arid desert climates, the thermal performance of passive buildings is strongly influenced by external climatic factors such as solar radiation, air temperature, humidity, and wind speed. However, these challenges can be mitigated through a judicious selection of construction materials and the optimization of their properties to ensure occupant thermal comfort. This study aims to identify the optimal combinations of insulation and wall thickness in straw-reinforced adobe structures to enhance the energy performance of buildings in a Moroccan desert context, specifically in the city of Errachidia. To achieve this aim, the study employs a validated energy model to investigate two key parameters: (1) the addition of natural fiber insulation (0.10 m) and (2) the variation of wall thickness (0.3 m to 0.5 m). The thermal simulation results indicate that adding 0.10 m of insulation significantly enhances thermal performance compared to non-insulated walls. Without insulation, wall thicknesses ranging from 0.4 m to 0.5 m reduce thermal fluctuations by 2°C. However, with insulation, a 0.3 m thick wall achieves a reduction of 3.7°C in summer indoor temperature peaks and maintains winter indoor temperatures as high as 12.1°C, even under extreme outdoor conditions. The integration of eco-friendly insulation panels also leads to a 23.18% reduction in cooling energy demand and a 40% decrease in heating needs compared to uninsulated walls. These findings underscore the importance of designing walls specifically tailored to the climatic conditions of desert regions, especially those near the city of Errachidia to optimize energy efficiency, lower ecological footprints, and promote sustainable architectural practices.

Theoretical Insights into a High-Performance Optical Absorption in GaSeS/InSeS 2D van der Waals Heterostructure for Photovoltaic Applications

Hanan Ziani — 2025-10-30

Advances in heterostructure design are transforming electronic and optoelectronic technologies, with particular focus on Janus monolayer-based heterojunctions. These heterojunctions, arising from the broken symmetry of 2D materials, offer new possibilities for ultra-thin, high-performance vertical p-n heterojunction solar cells. In this study, we examine the electronic structure and optical properties of a 2D GaSeS/InSeS heterostructure, formed through van der Waals interactions, based on first-principles calculations using density functional theory (DFT). The heterostructure consists of Janus group III chalcogenide GaSeS and InSeS monolayers (MLs).

The electronic properties show that both the AA and AB stacking configurations exhibit indirect semiconductor band gaps, with values of 1.3207 eV and 1.3452 eV using the PBE (Perdew-Burke-Ernzerhof) functional, and 2.0997 eV and 2.1242 eV using the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional, respectively. Both configurations also display the characteristic features of type-II heterojunctions, which promote efficient separation of photogenerated electrons and holes. Charge density analysis reveals a transfer of charge from GaSeS to InSeS.

Furthermore, optical analysis shows that both stacking configurations (AA and AB) exhibit similar absorbance spectra, primarily in the UV range, with peak absorption around 11.6 × 10⁵ cm⁻¹. Within the visible spectrum, the maximum absorption rate for both configurations is 2.8 × 10⁵ cm⁻¹. The 2D GaSeS/InSeS heterostructure holds great potential as a high-performance material for future photovoltaic devices, with promising applications in both photovoltaic cells and optoelectronic systems.