Design and fabrication of MoO3 nanoparticles incorporated PEDOT:PSS hybrid thin films for ITO-free organic solar cells

Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) hole contact is widely used in organic solar cells (OSCs). In this work, we report the effort to develop a versatile solution-processed molybdenum trioxide (s-MoO₃) thin films’ hole contact for application in PEDOT:PSS-free OSCs. Prepared products were characterized by field-scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, diffuse reflectance spectroscopy, X-ray photoelectron microscopy, BET-BJH and Raman spectroscopy. N₂ absorption–desorption results reveals that MoO₃/PEDOT:PSS delivers a high surface area (93.8 m²/g) and pore size (28.32 nm) than compared with pristine thin films. After adding MoO₃ to the PEDOT:PSS, device performance increased, with Jsc and FF values increasing to 16.01 mA cm² and 52.6%, respectively, with Voc values remaining unchanged (0.721 V). As a result of the synergic effect between MoO₃ NPs and PEDOT:PSS nanosheets, the PCE was enhanced to 5.56%, resulting in better hole mobility of the hybrid electrode. The successful operation of PEDOT:PSS-free OSCs indicates simpler fabrication steps for cost-effective OSCs and elimination of interfacial reactions caused by the acidic PEDOT:PSS layer for reliable OSCs.