Spray pyrolysis of a ZnO electron transport layer for hybrid organic-inorganic light-emitting diodes (HyLEDs) was investigated at substrate temperatures (Ts) between 150 and 450 °C to understand the effect of temperature on film properties and device performance. Characterization of ZnO thin films by X-ray Diffraction (XRD) and Atomic Force Microscopy (AFM) was performed and compared to the optoelectronic performance of HyLEDs with the architecture ITO/ZnO/F8BT/MoO3/Au. It was found that efficient devices can be obtained at temps. as low as 250 °C as opposed to the most widely used 450 °C. These findings are significant for offering a route to low-cost, faster processing of air-stable light-emitting diodes.