Solar Energy Materials & Solar Cells 91 (2007) 1647–1651 Solar cells parameters evaluation considering the series and shunt resistance K. Bouzidi, M. Chegaar à , A. Bouhemadou Physics Department, Ferhat Abbas University, 19000 Se´tif, Algeria Received 21 December 2006; accepted 4 May 2007 Available online 26 June 2007 Abstract This paper presents a new technique for the evaluation of the parameters of illuminated solar cell with a single diode lumped circuit model and considering the series and shunt resistances. This method includes the presentation of the standard I ¼ f(V) function as V ¼ f(I) and the determination of the factors C 0 , C 1 , C 2 of this function that provide the calculation of the illuminated solar cell parameters. These parameters are usually the saturation current (I s ), the series resistance (R s ), the ideality factor (n), the shunt conductance (G sh ¼ 1/R sh ) and the photocurrent (I ph ). Parameter values were extracted using the present method from experimental I–V characteristics of commercial solar cells and modules. The method proposed below appears to be accurate even in the presence of noise and/or random errors during measurement and it needs no a prior knowledge of the parameters compared to other methods. r 2007 Elsevier B.V. All rights reserved. Keywords: Solar cells; Parameters extraction; Illumination 1. Introduction An accurate knowledge of solar cell parameters from experimental data is of vital importance for the design, quality control of solar cells and for estimates of their performance. Several methods for the determination of G sh , I ph , R s , I s , and n are proposed by several authors [1–15]. Some of the methods involve measurement of illuminated I–V char- acteristics at single or different levels of illumination [1–6], some use dark conditions [7–10], while other utilizes dark and illumination measurements [9–12]. Recent methods use the measured current voltage characteristics and the subsequently calculated conductance of the device [13,14]. A review of techniques to determine the ideality factor and or the series resistance of solar cells has been given by Mialhe et al. [15] and Bashahu et al. [16]. In addition a comparative study of extraction methods for solar cell parameters has been dealt with in a previous paper [17]. Recent works have been published [18–22] and present new methods in order to compute the different parameters of interest. Authors [18] have presented interesting mathematical techniques that introduce new formulations to extract the single exponential model parameters of plastic solar cells. The high performance of these methods is inferred after application to devices with very high series and shunt lost. A study in simulation [20] is concerned with organic solar cells, which are generally characterized by 2–4 order of magnitude larger series resistance values and by relatively small shunt resistance values and where the photocurrent is generally about 1000 times smaller than for classical silicon cells. The study considers the effects on the IV characteristic, of any changes in the parameters values. Recently, a numerical method using a combination of lateral and vertical optimization was used [22] to extract the parameters of an illuminated solar cell. In addition, least-squares numerical techniques [23–30] have been proposed. Among the latter and of interest for us here for the sake of comparison, is a non-linear least- squares optimization algorithm based on the Newton ARTICLE IN PRESS www.elsevier.com/locate/solmat 0927-0248/$ - see front matter r 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.solmat.2007.05.019 à Corresponding author. Tel.: +213 5 91 28 59. E-mail address: chegaar@yahoo.fr (M. Chegaar).