Spray deposited gallium doped zinc oxide (GZO) thin film as the electron transport layer in inverted organic solar cells

Fig: (a) Schematic illustration of IOSC, (b) J-V characteristics of spray deposited GZOs as the ETL in IOSCs. [Display omitted] •Fabrication of highly transparent and conducting GZO film by spray technique.•Effect of DC voltage during the spray deposition of GZO films.•GZO thin film used in inverted organic solar cells (IOSCs) as electron transport layer (ETL).•GZO deposited under DC voltage of 2000V showed the PCE of 6.5% in IOSCs.•Low-cost environment friendly GZO can be effectively used as ETL in IOSCs. The electric field-assisted spray deposition of highly conducting and transparent gallium doped zinc oxide (GZO) films, with noticeable improvement in optical, structural, and electrical properties, is reported for application in organic photovoltaics with superior device performance. The GZO films deposited with applied voltages of 0 and 2000V to the nozzle exhibited an improved electrical resistivity of ∼1.8 × 10−3 Ω-cm and a transmittance (in the visible region) of over 80% for the films deposited under electric field, which can be used as electron transport layer (ETL) in inverted organic solar cells (IOSCs- ITO/GZO/PTB7:PC71BM/MoO3/Ag). Improved photovoltaic performance (power conversion efficiency: 6.5%) is obtained for the IOSC devices fabricated GZO ETL with the applied voltage of 2000V in comparison to the device fabricated using GZO ETL with the applied voltage = 0V (power conversion efficiency: 5.8%).