Electron. Mater., Volume 4, Issue 3 (September 2023) – 3 articles

Dye-sensitized solar cells (DSSCs) hold unique promise in solar photovoltaics owing to their low-cost fabrication and high efficiency in ambient conditions. However, to improve their commercial viability, effective, and low-cost methods must be employed to enhance their light harvesting capabilities, and hence photovoltaic (PV) performance. Improving the absorption of incoming light is a critical strategy for maximizing solar cell efficiency while overcoming material limitations. Mesoporous silica nanoparticles (MSNs) were employed herein as a reflective layer on the back of transparent counter electrodes. Chemically synthesized MSNs were applied to DSSCs via bar coating as a facile fabrication step compatible with roll-to-roll manufacturing. The MSNs diffusely scatter the unused incident light transmitted through the DSSCs back into the photoactive layers, increasing the absorption of light by N719 dye molecules. This resulted in a 20% increase in power conversion efficiency (PCE), from 5.57% in a standard cell to 6.68% with the addition of MSNs. The improved performance is attributed to an increase in photon absorption which led to the generation of a higher number of charge carriers, thus increasing the current density in DSSCs. These results were corroborated with electrochemical impedance spectroscopy (EIS), which showed improved charge transport kinetics. The use of MSNs as reflectors proved to be an effective practical method for enhancing the performance of thin film solar cells. Due to silica’s abundance and biocompatibility, MSNs are an attractive material for meeting the low-cost and non-toxic requirements for commercially viable integrated PVs. Full article

In this work, we report on the deposition of microcrystalline silicon (µc-Si:H) films produced from silane (SiH₄), hydrogen (H₂), and argon (Ar) mixtures using the plasma-enhanced chemical vapor deposition (PECVD) technique at 200 °C. Particularly, we studied the effect of RF power on the crystalline fraction (X_C) of the deposited films, and we have correlated the X_C with their optical, electrical, and structural characteristics. Different types of characterization were performed in the µc-Si:H film series. We used several techniques, such as Raman scattering spectroscopy, Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM), among others. Our results show that RF power had a strong effect on the X_C of the films, and there is an optimal value for producing films with the largest X_C. Full article