Fabrication of high-performance F and Al co-doped ZnO transparent conductive films for use in perovskite solar cells

Abstract

Fluorine and aluminum co-doped ZnO (FAZO) films were deposited on glass substrates by RF magnetron sputtering. The effects of the substrate temperature (Tsub) on the structural, morphological, electrical, and optical properties of the films were investigated by X-ray diffraction analysis, atomic force microscopy, photoluminescence spectroscopy, Hall effect measurement, and ultraviolet–visible–near infrared spectrophotometry. All the thin films showed typical wurtzite structure with the c axis preferentially oriented perpendicular to the substrate. With increasing Tsub, the grain size shows a parabolic-like enhancement; the film surface became relatively smooth and dense, and the crystallinity was also improved. At Tsub = 320 °C, the films showed the best electrical properties, with a resistivity of 3.53 × 10−4 Ω cm, Hall mobility of 39.33 cm2/V s, and carrier concentration of 4.50 × 1020 cm−3. An optical transmittance of more than 80% in a wide wavelength range from 400 to 1200 nm was also achieved. Perovskite solar cells employing the FAZO film had a higher power conversion efficiency than reference cells using F-doped SnO2 and Sn-doped In2O3, demonstrating its suitability for application in high-efficiency solar cells.