Solution modification of PEDOT:PSS inks for ultrasonic spray coating

PEDOT:PSS is a high-conductivity hole-transporting polymer that is widely used in polymer and perovskite photovoltaic devices, as well as in a host of other antistatic applications. Here we show that modification of PEDOT:PSS inks using ternary solvents and by the addition of small amounts of a high molecular weight polymer make it possible to deposit highly uniform thin films via ultrasonic spray coating. Such films can be deposited using a single pass in the wet phase without the use of surfactants; a process that greatly simplifies their deposition. Using this technique we create films having thickness and roughness comparable to that of spin coated films, whilst properties such as the conductivity and stability can be improved.