Large-area spray deposited Ta-doped SnO2 thin film electrode for DSSC application

• Published in: Solar energy Vol. 211; pp. 547 - 559
• Main Authors: Ramarajan, R., Purushothamreddy, Nandarapu, Dileep, Reshma K, Kovendhan, M., Veerappan, Ganapathy, Thangaraju, K., Paul Joseph, D.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 15.11.2020; Pergamon Press Inc
• Subjects: Carrier density; DSSC; Dye-sensitized solar cells; Electrical resistivity; Electrodes; Figure of merit; Morphology; Optical properties; Photovoltaic cells; Pyrolysis; Resistance stability; Sheet resistance; Solar cells; Solar energy; Spray pyrolysis; Surface work function; Ta-doped SnO2; Thin films; Tin dioxide; Transparent conducting oxide; X ray photoelectron spectroscopy; Surface work function; Resistance stability; Sheet resistance; Transparent conducting oxide; Ta-doped SnO2; DSSC
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2020.09.042

•10 × 10 cm2 Ta-doped SnO2 thin film is deposited by facile spray pyrolysis method.•Optical transmittance of TTO film was 81% at 550 nm.•Sheet resistance of 26 Ω/□ was achieved by doping Ta into SnO2.•TTO film exhibited resistance stability for post annealing upto 400 °C.•Power conversion efficiency of 3.26% is observed for DSSC using TTO electrode. Large-area (10 × 10 cm2) Ta-doped SnO2 (TTO) thin film was deposited by a facile spray pyrolysis method. The crystallinity, phase purity, and texture properties of the film are studied using XRD analysis. The XPS study confirmed the charge state of Sn to be in 4+, O1s in 2−, and Ta to be in 5+ state. A homogeneous polyhedron morphology was witnessed owing to the Ta dopant effect. The TTO film was highly transparent in the visible to near infrared region (NIR) with an average transmittance value of 81% at 550 nm. The TTO film was having a free carrier concentration of 5.42 × 1021 cm−3 and mobility of 41.7 cm2/Vs. The 4 wt% Ta doped SnO2 electrode exhibits a low sheet resistance of 26 Ω/□ and a high figure of merit value of 6.15 × 10−3 Ω−1. The resistance stability of sheet resistance was fairly good up to 400 °C indicating suitability of the TTO electrode to serve as conducting photoanode/counter electrode in dye-sensitized solar cell (DSSC) device. The DSSC device fabricated with the TTO electrode exhibited appreciable efficiency of 3.26% which is attributed to the enhanced electrical and optical properties by way of doping with Ta element.