A criterion of the degradation/oxidation susceptibility of organic photovoltaic (OPV) cells in aqueous solutions was proposed for the first time. The criterion was derived based on calculating the limit of the ratio value of the polarization resistance of an OPV cell in aqueous solution (Rps) to the polarization resistance of the OPV cell in air (Rpair). In other words, the criterion lim(Rps/Rpair)=1 was applied to determine the degradation/oxidation of the OPV cell in the aqueous solution when Rpair became equal (increased) to Rps as a function of time of the exposure of the OPV cell to the aqueous solution. This criterion was not only used to determine the degradation/oxidation of different OPV cells in a simulated operational environment but also it was used to determine the electrochemical behavior of OPV cells in deionized water and polluted water with fine particles of sand. The values of Rps were determined by the electrochemical impedance spectroscopy at low frequency. In addition, the criterion can be applied under diverse test conditions with a predetermined period of OPV operations.

Professor Khaled Habib holds a Ph.D in Chemical and Materials Engineering from the Optical Science and Technological Center of University of Iowa, Iowa City, Iowa, USA, 1988.   Mr.Habib was a Post Doctoral Fellow at the Chemical Engineering Dept., and Materials science Dept., of the Technical University of Aachen, Aachen, Germany, 1991-1992.      Mr. Habib specializes in “Laser optical interferometry as non-destructive testing (NDT) methods of materials evaluation in corrosive media, corrosion, and nano-structures of metallic glasses”.   Mr. Habib has in his credit more than 134 articles in international refereed journals in his area of specialization.   He is a fellow of the International Society of Photo- electronics, and Optics (SPIE),(http://spie.org/x38.xml).