Composite Film of Vanadium Dioxide Nanoparticles and Ionic Liquid–Nickel–Chlorine Complexes with Excellent Visible Thermochromic Performance

Vanadium dioxide (VO₂), as a typical thermochromic material used in smart windows, is always limited by its weaker solar regulation efficiency (Δ<i>T</i>_sol) and lower luminous transmittance (<i>T</i>_lum). Except for common approaches such as doping, coating, and special structure, compositing is another effective method. The macroscopic thermochromic (from colorless to blue) ionic liquid–nickel–chlorine (IL–Ni–Cl) complexes are selected in this paper to be combined with VO₂ nanoparticles forming a composite film. This novel scheme demonstrates outstanding optical properties: Δ<i>T</i>_sol = 26.45% and <i>T</i>_lum,l = 66.44%, <i>T</i>_lum,h = 43.93%. Besides, the addition of the IL–Ni–Cl complexes endows the film with an obvious color change from light brown to dark green as temperature rises. This splendid visible thermochromic performance makes the composite film superior in function exhibiting and application of smart windows

Achieving High Current Density of Perovskite Solar Cells by Modulating the Dominated Facets of Room-Temperature DC Magnetron Sputtered TiO₂ Electron Extraction Layer

The short circuit current density of perovskite solar cell (PSC) was boosted by modulating the dominated plane facets of TiO₂ electron transport layer (ETL). Under optimized condition, TiO₂ with dominant {001} facets showed (i) low incident light loss, (ii) highly smooth surface and excellent wettability for precursor solution, (iii) efficient electron extraction, and (iv) high conductivity in perovskite photovoltaic application. A current density of 24.19 mA cm^–2 was achieved as a value near the maximum limit. The power conversion efficiency was improved to 17.25%, which was the record value of PSCs with DC magnetron sputtered carrier transport layer. What is more, the room-temperature process had a great significance for the cost reduction and flexible application of PSCs