Indium tin oxide-free PEDOT:PSS/SAM/MoO3/Au/MoO3 multilayer electrodes for organic solar cells

A MoO3/Au/MoO3 (MAM) tri-layer structure was developed as a transparent, low-resistance anode for use in organic solar cells. Transmittance was maximized at 82% using symmetric bottom and top MoO3 layers (each of thickness 30 nm) either side of a 12 nm Au layer. Low sheet resistance also resulted (7.4 ohm per square). The series resistance and optical transmission of devices employing these structures as anodes were tailored by varying the thickness of the top MoO3 layer. Dissolution of the top MoO3 layer in

PSS degraded the cells, which could be decreased by the deposition of a self-assembled monolayer of 16-phosphonohexadecanoic acid on the MoO, prior to spin-coating the

PSS. Cells fabricated on

PSS/SAMs/MAM multilayer electrodes showed a power conversion efficiency of 2.33%, comparable to that of ITO-based organic solar cells. The

PSS/SAMs/MAM electrode was shown to be a promising replacement of ITO for use in low-cost optoelectronic devices.