Modelling solar cell S-shaped I-V characteristics with DC lumped-parameter equivalent circuits a review

Abstract

This article reviews and appraises the dc lumped-parameter equivalent circuit models that have been proposed so far for representing some types of solar cells that can exhibit under certain circumstances a detrimental S-shaped concave deformation within the energy-producing fourth quadrant of their illuminated I-V characteristics. We first present a very succinct recollection of lumped-parameter equivalent circuits that are commonly used to model conventional solar cells in general. We then chronologically present and discuss lumped-parameter equivalent sub-circuits that, combined with conventional solar cell equivalent circuits, are used to specifically represent the undesired S-shaped behaviour. The mathematically descriptive equations of each complete equivalent circuit are also examined, and closed form solutions for the terminal current and voltage as explicit functions of each other are presented and discussed whenever available. While comparing the most salient features and explaining the practical advantages and disadvantages of such equivalent circuit models, we offer some comments on possible directions for further improvement.

Extracting voltage-dependent series resistance of single diode model for organic solar cells

“…Both S-kink and voltage-dependent photocurrent can also be caused by space charge limitation (SCL) [58], interfacial energy barriers shifting and charge transport dissociation and recombination [38]. In order to model these phenomena a voltage-dependent current source or additional diodes should be included in the model [18].…”

“…4 a An example of using the WRA introduced in Eq. (18). b The corresponding regression error percentage.…”

“…Also, by using relation (18) and the proposed WRA, the voltage dependent series resistances ( R s (V ) ) for all the cells under test can be extracted from J-V characteristics. The results are presented in Fig.…”

“…Table 4 compares the MSE of the fitting process of GA extraction to those of the new WRA approach. For a better comparison, the series resistances extracted using relations (12), (13), (16) and (18) along with the extracted voltage dependent are illustrated in a separate diagram for each cell variant in Fig. 6.…”

A Lumped-Parameter Equivalent Circuit Modeling for S-Shaped I–V Kinks of Organic Solar Cells

“…Among these properties, current-voltage (I-V) curve, power-voltage (P-V) curve, fill-factor (FF), and power-conversion efficiency (PCE) are four key characteristics. As one of the most important characteristics, the I-V curve is commonly simulated by the conventional lumped-parameter equivalent circuit models including only one diode or multiple diodes [5,6]. However, these conventional models from [5,6] fail in explaining the S-shaped kinks [7,8] emerging near the open-circuit voltage (V oc ) point of OSCs.…”