Nanostructured TiO2 Films with a Mixed Phase for Perovskite Solar Cells

A series of thin films made with TiO2 nanoparticles with a varied anatase/rutile phase ratio is prepared on conducting glass substrates using a spin-coating method. The structure, morphology, and optical properties of TiO2 nanopowders and thin films fabricated are studied using powder X-ray diffraction, scanning electron microscopy, and optical spectroscopy. The TiO2 nanostructured films created are used as photoelectrodes for the fabrication of perovskite solar cells (PSCs). The photovoltaic characteristics of PSCs under AM1.5 light illumination (1000 W/m2) under ambient conditions are studied. It is shown that the best efficiency of solar-to-electrical energy conversion, namely, 9.3%, is obtained for the PSC with a photoelectrode based on a TiO2 film with an anatase/rutile mixed phase ratio of 86/14%.