International Seminar on Science and Technology, ISSTEC 2009, Yogyakarta, Indonesia

Problems in Determining Two Diodes Equivalent Circuit Parameters of Organic Solar Cell Using Reverse Bias Characteristic

Kuwat Triyana, Sholihun, Budi Prabowo Soewondo, Timothy Siahaan and Kamsul Abraha

Physics Department, Faculty of Mathematics and Natural Sciences, Gadjah Mada University
Sekip Utara BLS 21, Yogyakarta 55281, Indonesia

e-mail: triyana@ugm.ac.id, lion_avs@yahoo.com

Abstract. An equivalent circuit parameters of heterojunction bilayer copper phthalocyanine/perylene organic solar cell for one diode model have been accurately calculated in our previous work. The calculation has been performed based on reverse bias characteristic using an assumption that there will be a linear profile near the breakdown voltage on the current-voltage (J-V) curve. The confirmation has been clarified by comparing the curve from this model with the curve obtained from the experiment. The result gives a very good fitting to the current density-bias voltage curve in that we cannot distinguish the curve from our model with the one from the experimental data. However, since we still have problem in describing the physics mechanism based in our previous work, we are going to continue our investigation through the recent work. For instant, it is still difficult for us to determine whether the shunt resistance is a result from the bulk or from the interface. In the recent study, we found that problems came up when we applied this approach to the two diodes model such as the negative value of shunt resistance (Rp), while the value of series resistance (Rs) exceed the value of Rp. These problems contrary to the reality that Rp must be positive and the value of Rs is always smaller than Rp. Hopefully, the problems presented in this paper can give useful information to the development of the research to increase the efficiency of organic solar cell in the future.

Keywords: two diodes equivalent circuit model, photovoltaic device, reverse bias characteristic