Low-temperature MoO3film from a facile synthetic route for an efficient anode interfacial layer in organic optoelectronic devices

A low temperature solution-processed MoO3 (sMoO3) thin film with a facile method for organic optoelectronic devices is developed. The film is extremely smooth with a root mean square (RMS) roughness of 0.318 nm, which is a significant advance for fabricating devices. An X-ray photoelectron spectroscopy (XPS) measurement shows that the sMoO3 possesses few Mo5+ states with a Mo : O stoichiometry of 2.99, demonstrating a nearly ideal MoO3 stoichiometry at a low annealing temperature. The sMoO3 film exhibits a superior hole injection ability in both an organic light-emitting diode (OLED) and organic photovoltaic cell (OPV), compared to conventional hole injection material poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). It is proved that the sMoO3 fabricated by the simple and low-cost method is an excellent alternative to a PEDOT:PSS anode buffer layer for solution-processed organic optoelectronic devices.