Rapid and Accurate Measurement of Ideality Factor and Parasitic Resistances of Thin Film Solar Cells

Abstract

The sunshade method for the measurement of the ideality factor and resistances of solar cells is commonly used in silicon solar cells. However, the method is rarely employed for thin-film solar cells. In this paper, the sunshade method is applied to CIGS solar cells, and it is shown that the three major assumptions of the method remain valid for CIGS solar cells. The extracted parameters are compared to those calculated using other common methods, and the ideality factors and R s values are quickly determined and found to be nearly the same as those extracted through illuminated I-V fitting and dark I-V fitting.

Influence of the ideality factor on the series resistance for some analytical methods of parameters extraction of PV panels

“…Within this class, most methods generate Rs(M) profiles that are practically linear in the considered interval of M. It is worthy to notice that the expressions of Rs(M) given by the second class intersect each other almost closer to the values of Rs and M given by the methods of the first class, as shown in Figure 1 and Figure 2 (points located by blue squares in Figure 8 and Figure 9). It Moreover, available experimental studies expressing graphically the relation between Rs and M show rather a linear relation between them (Park et al, 2018;Rana et al, 2018). This fact proves also that the profile of Rs(M) given by (method 1 and method 4) is qualitatively in agreement with the few available experimental results.…”

“…It has also shown that there are many theoretical and some experimental studies dedicated to analyzing the influence of the extracted parameters on different quantities such as the current, voltage, temperature, illumination and to some data related to the three points (Bashahu & Nkundabakura, 2007;Dandoussou et al, 2015;El Tayyan, 2015;Singh & Ravindra, 2011;Venkateswari & Rajasekar, 2021). On the other hand, very few experimental studies can be found that highlight the interdependency between parameters such as the series resistance and the ideality factor (Park et al, 2018;Rana et al, 2018). This lack justifies our interest to carry out this study.…”

Impact of Buffer Layer Process and Na on Shunt Paths of Monolithic Series-connected CIGSSe Thin Film Solar Cells

“…Thus, the CIGSSe solar cells were fabricated three times using the same process but in different batches in order to compare the characteristics of the CIGSSe solar cells with CBD and ALD buffer layers by means of statistical analysis. The illuminated I–V parameters of the CIGSSe solar cells (with the dimensions of 300 mm × 320 mm evenly cleaved from the corresponding 5G-size solar cells) were measured and calculated by using Sunshade method 7 . Figure 2 shows the box plots of the photo conversion efficiencies, open circuit voltages, short circuit currents, fill factors, shunt resistances, series resistances, and diode ideality factors for the CIGSSe solar cells with the CBD and ALD buffer layers.

Figure 2Illuminated I–V parameters of the CIGSSe solar cells with CBD and ALD buffers fabricated in three distinct process batches.

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“…This is because under shade conditions, the low shunt resistance of solar cells decreases their open circuit voltage, as reported by Park et al . 7 . Thus, high diode ideality factor of CIGSSe solar cell with ALD buffer is attributed not to junction recombination but to the measurement error caused by low shunt resistance.…”

“…To evaluate the characteristics of the CIGSSe solar cells with the two buffer layers, their illuminated I–V characteristics were measured using an AM 1.5 G solar simulator at 25 °C. The shunt resistance of the solar cells was defined by the Sunshade method 7 . Shunt resistances of coupon solar cells were measured by fitting the dark I–V curve using a one-diode model.…”