Anti-reflection coating (ARC) plays an important role in reducing the reflection of incident light and absorbing more photons to produce more photoelectrons. In this paper, a single-layer TiO2 anti-reflection coating is performed on GaAs solar cells. In the simulation study, we compared the solar cell before and after ARC by using PC1D simulation software. The I–V characteristics, reflectance, and external quantum efficiency have been simulated with a refractive index of 2.324 at 600 nm wavelength. The simulated results show that the ARC-coated solar cell performs better. It is found that the power conversion efficiency of 24.75% reflection is 9.5%, and the EQE is 95% at the 62 nm thickness of the ARC layer. The optimized reflectivity was found to be around 5%, which is quite lower than that without ARC (32%).

The energy conversion efficiency (ECE) ($\eta$), current density (J_sc), open-circuit voltage (V_oc), and fill factor (ff) of perovskite solar cells were studied by using the transmittance of a nanopatterned mesoporous TiO₂ (mp-TiO₂) thin-film layer. To improve the ECE of perovskite solar cells, a mp-TiO₂ thin-film layer was prepared to be used as an electron transport layer (ETL) via the nanoimprinting method for nanopatterning, which was controlled by the aspect ratio. The nanopatterned mp-TiO₂ thin-film layer had a uniform and well-designed structure, and the diameter of nanopatterning was 280 nm. The aspect ratio was controlled at the depths of 75, 97, 127, and 167 nm, and the perovskite solar cell was fabricated with different depths. The ECE of the perovskite solar cells with the nanopatterned mp-TiO₂ thin-film layer was 14.50%, 15.30%, 15.83%, or 14.24%, which is higher than that of a non-nanopatterned mp-TiO₂ thin-film layer (14.07%). The enhancement of ECE was attributed to the transmittance of the nanopatterned mp-TiO₂ thin-film layer that is due to the improvement of the electron generation. As a result, better electron generation affected the electron density, and J_sc increased the V_oc, and ff of perovskite solar cells.

To unlock the full potential of PSCs, machine learning (ML) was implemented in this research to predict the optimal combination of mesoporous‐titanium dioxide (mp‐TiO₂) and weight percentage (wt%) of phenyl‐C₆₁‐butyric acid methyl ester (PCBM), along with the current density (J_sc), open‐circuit voltage (V_oc), fill factor (ff), and energy conversion efficiency (ECE). Then, the combination that yielded the highest predicted ECE was selected as a reference to fabricate PCBM‐PSCs with nanopatterned TiO₂ layer. Subsequently, the PCBM‐PSCs with nanopatterned TiO₂ layers were fabricated and characterized to further understand the effects of nanopatterning depth and wt% of PCBM on PSCs. Experimentally, the highest ECE of 17.338% is achieved at 127 nm nanopatterning depth and 0.10 wt% of PCBM, where the J_sc, V_oc, and ff are 22.877 mA cm⁻², 0.963 V, and 0.787, respectively. The measured J_sc, V_oc, ff, and ECE values show consistencies with the ML prediction. Hence, these findings not only revealed the potential of ML to be used as a preliminary investigation to navigate the research of PSCs but also highlighted that nanopatterning depth has a significant impact on J_sc, and the incorporation of PCBM on perovskite layer influenced the V_oc and ff, which further boosted the performance of PSCs.

Renewable energy is in high demand, with significant contributions from the solar industry encouraging research into more efficient, cost-effective, and versatile solar cell technologies. Anti-reflection coating (ARC) is an important method for improving solar cell efficiency by minimizing light reflectance and maximizing photon absorption. This study investigates the electrical and optical behaviors of single- and double-layer ARCs for gallium arsenide (GaAs) solar cells, using PC1D simulation for single-layer SiO₂, and ZnSe, and double-layer SiO₂/ZnSe configurations. The findings indicate that the double-layer SiO₂/ZnSe ARC structure significantly reduces reflectance and enhances light absorption, leading to a higher current density (J_sc) and overall efficiency. With optimized layer thicknesses of 60 nm (ZnSe) and 100 nm (SiO₂), the efficiency increased from 20.628% to 30.904%, representing a 49.81% improvement. This enhancement is primarily attributed to the increased photon absorption and a higher electron–hole generation rate, confirming the superior performance of double-layer ARCs over single-layer configurations.

Dye-sensitized solar cells (DSSCs) are known for their excellent low-light performance, cost-effectiveness, and flexibility. The photoanode has a crucial role in enhancing the overall performance of DSSCs and can be modified with different nanostructures. This study explores the impact of photoanode structure on the power conversion efficiency (PCE) of DSSCs, where four configurations of freestanding TiO₂ nanotube arrays (f-TNAs), closed-up, closed-down, open-up, and open-down, were employed as photoanodes. Performance was evaluated based on current density (J_sc), open-circuit voltage (V_oc), fill factor (FF), and PCE concerning dye adsorption, electrolyte diffusion, electron transport, and barrier layer. DSSCs based on open configurations, open-up and open-down f-TNAs, demonstrated superior performance, achieving PCE of 7.73% and 7.71%, respectively. The primary distinction between the DSSCs based on open-up f-TNAs and those based on open-down f-TNAs lies in the dye adsorption time and electron diffusion characteristics. The PCE for DSSCs with closed-down f-TNAs was measured at 6.78%, while DSSCs with closed-up f-TNAs showed a lower PCE of 5.52%. The presence of a barrier layer under the bottom of f-TNAs impacted the PCE for DSSCs with closed-down f-TNAs, whereas for DSSCs with closed-up f-TNAs, insufficient dye loading, poor electrolyte diffusion and barrier layer reduced the performance.