Solar Energy and Sustainable Development Journal

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.

Improving PEM Water Electrolysis Efficiency with ANN-Based Control to Handle Rapid Photovoltaic Power Fluctuations

Abdellah EL IDRISSI — 2025-10-30

This research presents an innovative method for enhancing hydrogen production through proton exchange membrane (PEM) water electrolysis, powered by photovoltaic (PV) energy. The system is based on the Perturbation and Observation (P & O) method of Maximum Power Point Tracking (MPPT) with a boost converter to maximize energy capture, and a buck converter to stabilize DC voltage, ensuring compatibility with the proton exchange membrane electrolyzer. An artificial neural network (ANN)-based controller manages the buck converter, effectively minimizing the effects of solar irradiation fluctuations on electrolyzer performance. By using the adaptive learning capabilities of the ANN, the proposed approach increases the efficiency of hydrogen production under varying solar energy levels. Simulation results indicate that the ANN controller outperforms the conventional PI controller, reducing the mean absolute percentage error (MAPE) from 1.22 % to 0.95 %, decreasing overshoot from 12.84 % to 3.19 %, and achieving a faster settling time of 0.022 s compared to 0.023 s. This study advances renewable hydrogen production technologies, demonstrating that ANN-based control improves dynamic performance and contributes to the development of smarter, more resilient energy systems.

Optimization of Adobe and Sawdust-Based Bricks for Improved Energy Efficiency in Construction

Mohammed Benfars — 2025-10-30

The exploration of bio-based materials for sustainable construction practices, particularly through the use of locally sourced resources like sawdust, is the focus of this study, which evaluates the thermal performance of adobe bricks reinforced with 2% sawdust in small, medium, and large sizes, ranging from 0.3 to 2 cm. The bricks were manufactured using local materials, and the physicochemical properties of the clay were initially analyzed and characterized. The laboratory examined the bricks' thermophysical characteristics, such as their density, thermal conductivity, and heat capacity. The TRNSYS program was used to conduct annual thermal simulations based on representative meteorological data for a typical building in the semi-arid Moroccan city of Beni Mellal. The results indicate that the energy savings achieved in terms of both heating and cooling were comparable across all configurations of sawdust-reinforced adobe bricks. When compared to a reference concrete building, the heating energy demand was reduced by 59.14% for clay without sawdust, 72.61% for clay with small sawdust, 71.25% for clay with medium sawdust, and 69.88% for clay with large sawdust. Similarly, the cooling energy demand reductions were 45.71%, 58.82%, 57.68%, and 56.62%, respectively, for clay without sawdust, and with small, medium, and large sawdust. These findings suggest that the incorporation of sawdust, regardless of particle size, leads to similar energy savings, offering flexibility in utilizing locally available sawdust from Beni Mellal to optimize energy performance. This research highlights the importance of local clay-based materials and the use of sawdust as a natural reinforcement, to optimize the energy efficiency of buildings. It also offers new perspectives for their integration into sustainable construction practices, contributing to global sustainable development goals.

Optoelectronic Properties of Doped CaTiO₃ (C, N, Si and P):

Abdellah Bouzaid — 2025-10-30

This study uses density functional theory (DFT) with generalized gradient approximation (GGA) and modified Becke-Johnson potential (mBJ) to analyze the structural, electronic, and optical properties of perovskite materials, where indicates the number of dopant atoms at the oxygen (O) site. In this research, Y represents the elements C, N, Si, and P, which are substituted at oxygen sites with a doping concentration of x = 16%. Firstly, the structural optimization results reveal negative formation energies for both pure and doped CaTiO₃, confirming the stability. Moreover, doping with Y significantly reduces the bandgap energy compared to undoped CaTiO₃ (2.766 eV). Specifically, the band gaps for materials (Y = C, N, Si, and P) are reduced to 0.87, 1.63, 0, and 0.6 eV respectively. In addition, doping with C and N retains the nature of the indirect band gap, with electronic transitions between the Γ and L points of the Brillouin zone, whereas doping with P results in a direct band gap. Additionally, doping with Si reduces the band gap to zero, resulting in metallic behavior. Furthermore, the Fermi level (E_F) shifts towards the valence band (VB), indicating p-type semiconductor behavior for the doped systems, except , which exhibits metallic behavior. Finally, analysis of the optical properties shows that doping increases the static dielectric constant, ε₁(0), with specific values for each dopant 7.1 for , 6.72 for , 36.63 for , and 23.69 for . Notably, doping CaTiO₃ with 16% of Y reduces the bandgap, improving optical absorption and conductivity in the visible range, making (Y= C, N, Si, and P) a promising material for photovoltaic cells and optoelectronic applications.