Improved Morphology of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Thin Films for All-Electrospray-Coated Organic Photovoltaic Cells

Spray coating technique has been established as a promising substitute for the traditional coating methods in the fabrication of organic devices in many reports recently. Control of film morphology at the microscopic scale is critical if spray-coated devices are to achieve high performance. Here we investigate electrospray deposition protocols for the fabrication of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films with a single additive system under ambient conditions at room temperature. Critical deposition parameters including solution composition, applied voltage, and relative humidity are discussed systematically. Optimized process for preparing homogenous PEDOT:PSS thin films is applied to all-electrospray-coated organic photovoltaic cells and contributes to a power conversion efficiency comparable to that of the corresponding all-spin-coated device.