PVA/Pt/N-TiO2/SrTiO3 porous films with adjustable pore size for hydrogen production under simulated sunlight

Facile preparation of a water-based antireflective SiO2 film with high transmittance for perovskite solar cells

The synthesis of anti-reflective (AR) films has been increasingly focused on environmental friendliness and cost efficiency in order to realize green and sustainable development. Herein, a novel strategy for preparing a nanoporous SiO2 AR film with high transmittance by a sol-gel process is proposed based on a sodium silicate aqueous solution. Sodium ions in the as-prepared SiO2 AR film can be effectively removed by a facile washing process, and thus its refractive index can be regulated. Moreover, the pH value of the sol has a huge effect on the structure and properties of the SiO2 AR film. As a result, the AR film exhibited a high transmittance increase of 4.10% at 550 nm and an average transmittance increase by 3.51% in the wavelength range of 380-1100 nm compared with blank glass. In addition, the obtained water-based SiO2 AR film exhibited hydrophilicity and the water contact angle (WCA) can be regulated from 61° to 8.4°. When the AR film was applied to the upper surface of perovskite solar cells, the photoelectric conversion efficiency (PCE) revealed an improvement of 1.44% compared with the PCE of perovskite solar cells without the AR film. Therefore, this work can provide a facile and effective method to prepare water-based antireflective films with high transmittance for solar cells.

Structural Dependent Eu3+ Luminescence, Photoelectric and Hysteresis Effects in Porous Strontium Titanate

Eu³⁺ doped porous nanostructured SrTiO₃ films and powder fabricated by sol-gel route without using any precursor template are characterized by different morphology and phase composition. The films show red and yellow luminescence with the most intensive photoluminescence (PL) bands at 612 nm and 588 nm, respectively. Raman, secondary ion mass spectrometry (SIMS), and X-ray diffraction (XRD) analysis of undoped nanostructured porous SrTiO₃ films showed the presence of TiO₂, SrO, and SrTiO₃ phases and their components. The undoped porous SrTiO₃ films are photosensitive and demonstrate resistive switching. The capacitance-voltage hysteresis loops with the width of about 6 V in the frequency range of 2 kHz-2 MHz were observed.

Porous Polyvinyl Alcohol Membranes: Preparation Methods and Applications

Polymeric membrane technology is a constantly developing field in both the research and industrial sector, with many applications considered nowadays as mature such as desalination, wastewater treatment, and hemodialysis. A variety of polymers have been used for the development of porous membranes by implementing numerous approaches such as phase inversion, electrospinning, sintering, melt-spinning and cold-stretching, 3D printing, and others. Depending on the application, certain polymer characteristics such as solubility to non-toxic solvents, mechanical and thermal stability, non-toxicity, resistance to solvents, and separation capabilities are highly desired. Poly (vinyl alcohol) (PVA) is a polymer that combines the above-mentioned properties with great film forming capabilities, good chemical and mechanical stability, and tuned hydrophilicity, rendering it a prominent candidate for membrane preparation since the 1970s. Since then, great progress has been made both in preparation methods and possible unique applications. In this review, the main preparation methods and applications of porous PVA based membranes, along with introductory material are presented.