Fabrication of Photovoltaic Cell From Rhenium Containing Polymer

Abstract

Photovoltaic devices were fabricated using rhenium bis(arylimino) acenaphthene (DIAN) complex containing poly(p-phenylenevinylene). These polymers absorb strongly in the visible region at ca. 440-550 nm. In addition, this type of transition metal based polymers have been shown to exhibit large photo-sensitivity due to the presence of the rhenium complex, which has a relatively long-lived Metal-to-Ligand Charge Transfer (MLCT) character. By using this type of polymers, the metal content can be adjusted easily by simply changing the monomer feed ratio. Moreover, the excited state properties and electronic absorption properties can be modified by varying the structure of the diimine ligand coordinated to the metal. This approach allows us to fine-tune the absorption spectra of the polymers by employing different types of rhenium complex derivatives. PEDOT:PSS and PTCDI were used as the hole and electron transport layers, respectively. The ITO/PEDOT:PSS/DIAN-PPV/PTCDI/Al devices were found to exhibit photovoltaic response under the illumination of AMI solar radiation. The short-circuit current ISC, open-circuit voltage V OC, and the fill factor FF were measured to be 38 μA/cm 2, 0.93 V and 0.21 respectively. Another photovoltaic device was prepared with the structure ITO/PEDOT:PSS/DIAN-PPV:TiO2/PTCDI/Al and its photovoltaic properties were studied. The presence of TiO2 will assist the electron transport of the DIAN-PPV to the PTCDI, in which the electrons can be collected at the aluminium electrode. The short-circuit current ISC open-circuit voltage VOC, and the fill factor FF were measured to be 51 μA/cm2, 1.18 V and 0.12 respectively. It was observed that the power conversion efficiency of photovoltaic devices related closely to the rhenium content and the structure of the rhenium complex used.