In situ growth of columnar MoO₃ buffer layer for organic photovoltaic applications

Columnar MoO₃ in situ growth prepared from direct converting soluble Mo-containing precursor during active layer thermal annealing was utilized as anode buffer layer to fabricate organic bulk heterojunction photovoltaics. The columnar morphology could improve the interface contact between active layer and buffer layer. The structure and phase of in situ formed MoO₃ were studied by X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). We demonstrated that the organic photovoltaic devices based on P3HT:PC₆₁BM using in situ formed columnar MoO ₃ as anode buffer layer presented a high open-circuit voltage and fill factor leading to an efficiency of 3.92%, which is higher than the controlled PEDOT:PSS-based devices.