Facile synthesis and fabrication of a poly(ortho-anthranilic acid) emeraldine salt thin film for solar cell applications

Poly(o-anthranilic acid) emeraldine salt (PANA-ES) as a conjugated semiconductor polymer has been synthesized in an acidic medium based oxidative polymerization route. The identification of the PANA-ES powder has been carried out using the following techniques: FT-IR and UV-Vis. SEM has been used to investigate the morphology of the resulting PANA-ES powder. The structural properties of the resulting nanostructured PANA-ES thin film have been investigated by X-ray diffraction (XRD). The analysis of the spectral behavior characteristics of the nanostructured PANA-ES thin film, in the absorption region, displayed a direct and indirect allowed transition, and the fundamental energy gaps were estimated as (1.89, 3.24 eV) and (2.35, 4.06 eV), respectively. A hybrid (polymer/inorganic) heterojunction device built on PANA-ES (deposited by the spin coating technique onto a p-Si single crystal wafer) was fabricated. The dark I-V characteristics were determined at different temperatures in the range from 298 to 386 K of the Au/PANA-ES/p-Si/Al heterojunction diode. The device showed rectification behavior and an ideality factor of 85 at +/- 2 V and 3.229 determined at room temperature. Under the following different light intensities: 10.1, 15.3 and 20.5 W m(-2), the Au/PANA-ES/p-Si/Al showed photovoltaic performance data with a short circuit current (I-sc) and open circuit voltage (V-oc) of (0.09 mA 1,41 mV), (0.16 mA, 176 mV) and (0.26 mA and 211 mV), respectively. The filling factor (FF) and electrical conversion efficiency () of the Au/n-PANA-ES/p-Si/Al device were found to be 0.205 and 6.07%, respectively.