Enhanced efficiency of organic solar cells based on (MEH-PPV) with graphene and quantum dots

In this work, organic photovoltaic cells are fabricated using a spin coated composite active layer of organic electronic materials conjugated polymer poly[2-methyl-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) mixed with cadmium selenide (CdSe) quantum dots and graphene. The active layer is sandwiched between two metallic conductors, typically a layer of silicon and indium tin oxides (SiO2:ITO) with high work function of (4.3 eV) and a layer of low work function aluminum metal (3.7 eV) as anode and cathode respectively.Spectral properties were explored for thin films of pure MEH-PPV, CdSe, MEH-PPV:CdSe, and MEH-PPV:CdSe:graphene blends coated onto glass at a spin speed of 6000 rpm using a spectrophotometer for optical absorption in the visible region with various concentration and benzene as a solvent. The photoluminescence (PL) spectra of the pure quantum dots and blended MEH-PPV:CdSe with graphene from various concentrations were recorded. The current–voltage characteristics (I–V) of the solar cells showed that incorporation of the quantum dots and graphene in the copolymer resulted into further increase in the power conversion efficiency compared to that in their absence.