Poly(o-phenylenediamine) thin film for organic solar cell applications

Poly(ortho phenylenediamine) (PoPDA) microrods with ladder-type structure are synthesized in acidic medium (pH=0.5) at room temperature based on a developed and facile method. The molecular structure, thermal stability, and surface morphology of the microrods-shaped PoPDA were described by different characterization techniques comprising FTIR, TGA, (HNMR)-H-1, and SEM. Optimized thin films of PoPDA were successfully fabricated by thermal deposition method. The thin film was characterized by XRD and AFM. Au/PoPDA/p-Si/Al heterojunction diodes have been successfully fabricated. Dark current-voltage and capacitance-voltage characteristics were applied to get the particular parameters of the devices. Photovoltaic features of Au/PoPDA/p-Si/Al heterojunction at various intensities of white light illumination are studied. Under optimized conditions, the fabricated planar heterojunction solar cells utilizing a 95 +/- 10nm of PoPDA film exhibited a power conversion efficiency (PCE) of 5.64% (J(SC)=41.78A/m(2), V-OC=0.36V, and FF=28.11%). The relatively small FF (at room temperature with IP) and R-s of the devices designate that by increasing of the absolute temperature, the photovoltaic performance of the solar cells can be improved.