Aerogels, due to their unique features like lightweight, ultra-low thermal conductivity, and design variations, have gotten a lot of interest in thermal insulation, photocatalysis, and protective areas. Besides their superior thermal properties, aerogel thermal insulation and photocatalyst materials also possess many inherent flaws, such as handling issues, high manufacturing costs, and low strength as well as toughness. The most persuasive and successful ways to improve photocatalytic and thermal insulating qualities while lowering costs are composition optimization and microstructure reconstruction. Their high surface area and porosity make them ideal for enhancing the efficiency and capacity of these devices. Research may lead to more efficient and longer-lasting energy storage solutions. This review describes the characteristics, microstructural reconstruction, design variation, and properties of all aerogel fabrication techniques and provides a comprehensive overview of scientific achievements linked to them. The effectiveness of raw material compositions, properties, and mechanical parameters are also discussed. The major goal of this review is to highlight the aerogel-based materials and design variations and to explore the most potential development trends for photocatalysis and thermal applications. The industrial as well as technical applications of silica aerogels are also highlighted. This review highlights futuristic applications of aerogel-based textile materials to alleviate the CO₂ burden on our atmosphere, either by providing next-level thermal insulation or by employing them in CO₂ mitigating technologies such as CO₂ capture.

Perovskite solar cells (PSCs) compete with conventional solar cells regarding their low-temperature processing and suitable power conversion efficiency.

Ca-doped TiO₂ films were synthesized by the modified sol-gel method and employed as the electron transport material of perovskite solar cells (PSCs). Morphological, optoelectronic, thermal, and electrical studies of thin films were investigated through XRD, RAMAN, SEM, AFM, UV-Vis, FTIR, and IV characteristics. Ca doping was detected with the help of structural properties while morphological analysis revealed that thin films based on Ca-doped titania are crack-free, homogenous, and uniformly distributed. Further optoelectronic properties have shown a promising conversion efficiency of 9.79% for 2% Ca-doped titania followed by 1% Ca-doped titania, while 3% have shown the lowest conversion efficiency among these prepared samples. The 2% an optimized doping of Ca has shown an almost two-fold increase in conversion efficiency in comparison to pristine TiO₂, along with an increase in current density from 15 mA⋅cm⁻² to 19.3 mA⋅cm⁻². Improved energy efficiency and higher current density are attributed to faster electron transportation; moreover, the optimized percentage of Ca doping seems to be an effective approach to improve the PSCs’ performance.

ZnO and TiO₂ are both well-known electron transport materials; however, an exact comparison of their performance, when fabricated under the same synthesis conditions, is missing in the literature. Considering this, we introduced a viable electrospinning route for the development of highly polycrystalline TiO₂ and ZnO nanofibers for an electron transport material (ETM) of perovskite solar cells and photocatalysts for textiles. Thanks to the effective tuning of band structure and morphology of TiO₂, a significant improvement in performance as compared to ZnO was observed when both were used as photoanodes and photocatalysts. X-ray diffraction detected polycrystalline structural properties and showed that peaks are highly corresponding to TiO₂ and ZnO. Morphological analysis was carried out with a scanning electron microscope, which revealed that nanofibers are long, uniform, and polycrystalline, having diameter in the nano regime. TiO₂ nanofibers are more aligned and electron-supportive for conduction as compared to ZnO nanofibers, which are dense and agglomerated at some points. Optoelectronic properties showed that TiO₂ and ZnO show absorption values in the range of ultraviolet, and visible range and band gap values for TiO₂ and ZnO were 3.3 and 3.2 eV, respectively. The TiO₂ band gap and semiconductor nature was more compatible for ETL as compared to ZnO. Electrical studies revealed that TiO₂ nanofibers have enhanced values of conductivity and sheet carrier mobility as compared to ZnO nanofibers. Therefore, a higher photovoltaic conversion efficiency and antibacterial activity was achieved for TiO₂ nanofibers (10.33%), as compared to ZnO (8.48%). In addition, the antibacterial activity of TiO₂ was also recorded as better than ZnO. Similarly, compared to ZnO nanofibers, TiO₂ nanofibers possess enhanced photoactivity for antimicrobial and dye degradation effects when applied to fabrics.

The efficient electron transport layer (ETL) plays a critical role in the performance of perovskites solar cells (PSCs). Ideally, an unobstructed network with smooth channels for electron flow is required, which is lacking in the pristine TiO₂-based ETL. As a potential solution, here we tuned the structure of TiO₂ via optimized heteroatom doping of Al. Different concentrations (1, 2, and 3 wt%) of Al were doped in TiO₂ and were successfully applied as an ETL in PSC using spin coating. A significant difference in the structural, opto-electronic, chemical, and electrical characteristics was observed in Al-doped TiO₂ structures. The opto-electronic properties revealed that Al doping shifted the absorption spectra toward the visible range. Pure titania possesses a bandgap of 3.38 eV; however, after 1, 2, and 3% Al doping, the bandgap was linearly reduced to 3.29, 3.25, and 3.18 eV, respectively. In addition, higher light transmission was observed for Al-doped TiO₂, which was due to the scattering effects of the interconnected porous morphology of doped-TiO₂. Al-doped titania shows higher thermal stability and a 28% lower weight loss and can be operated at higher temperatures compared to undoped titania (weight loss 30%) due to the formation of stable states after Al doping. In addition, Al-doped TiO₂ showed significantly high conductivity, which provides smooth paths for electron transport. Thanks to the effective tuning of band structure and morphology of Al-doped TiO₂, a significant improvement in current densities, fill factor, and efficiency was observed in PSCs. The combined effect of better Jsc and FF renders higher efficiencies in Al-doped TiO₂, as 1, 2, and 3% Al-doped TiO₂ showed 12.5, 14.1, and 13.6% efficiency, respectively. Compared to undoped TiO₂ with an efficiency of 10.3%, the optimized 2% Al doping increased the efficiency up to 14.1%. In addition, Al-doped TiO₂ also showed improvements in antibacterial effects, required for photoactive textiles.