Free Access
Issue
Eur. Phys. J. Appl. Phys.
Volume 87, Number 3, September 2019
Article Number 30101
Number of page(s) 4
Section Semiconductors and Devices
DOI https://doi.org/10.1051/epjap/2019190037
Published online 08 November 2019

© EDP Sciences, 2019

1 Introduction

The study of the solar cells is a department of the scientific research which turns to new behaviors to be explained. This is because of the style of technology and substances used in the photovoltaic solar cells. Several works deal with thin layer elaboration techniques for getting these solar cells [1,2].

Photovoltaic technologies supply such an answer and have already been used for several years [3]. First of all, the usage of PVs was for generating power on space crafts and satellites [4] and later additionally for terrestrial uses [5]. Thin film CdS/CdTe solar cell has been an attractive alternative of traditional silicon solar cell due to their low price. The fabrication of CdS/CdTe solar power technology has step by step advanced to offer a cell with higher efficiency. The improvement of cadmium telluride based thin film solar cells commenced in 1972 with 6% efficient CdS/CdTe [6] to reach the prevailing top performance of 16.5% acquired by NREL researchers in 2002 [7]. Current CdTe technology exhibits a conversion efficiency of up to 19.6% (20.4% on small area 0.5 cm2) and up to 17.5% under standard test conditions (STC) for solar cells and PV modules, respectively [8,9]. An expansion of studies at the device modeling of CdTe solar cells has been conducted previously. The researches about how the back contact barriers, carrier lifetimes, CdTe film thickness, electron reflector and carrier densities impacting the properties of CdTe solar cells have been reported [1015]. So as to recognize the mechanisms for the enhancement of CdTe solar cells, a study of the modeling and simulations to examine the critical factors governing the efficiency of CdTe solar cells was applied.

Solar cell overall performance is directly affected by weather conditions, specifically the temperature and solar irradiance [16]. Many solar cell technologies have specific responses to temperature versions, and this difference in the reaction was widely considered previous [1724].

In the present research study, a numerical simulation of CdTe thin film solar cells has been carried out by using SCAPS-1D. The effect of temperature field on the CdTe solar cell is examine at variation with completely different in operating conditions. The variation of the cell parameters for example (Isc), (Voc) with its temperature along the time is additionally studied in regard to the efficiency. This can make it possible to assist one or extra of the published tendencies regarding the variation of the cell parameters and its efficiency with the cell temperature. Appropriate suggestions to growth the solar cell efficiency are given.

2 Methods and calculations

This studying is focused on one-dimensional simulation and SCAPS-1D has been used as the tool for the simulations of thin film CdS/CdTe solar cell. SCAPS-1D is a one dimensional, windows application solar cell simulation program developed at the Department of Electronics and Information Systems (ELIS) of the University of Gent, Belgium. SCAPS is originally developed for cell structures of the CuInSe2 and the CdTe family [23].

Our simulation tool predicts temporal variations in light current–voltage (JV) characteristics to calculate open-circuit voltage (Voc(t)), short-circuit current density (Jsc(t)) and fill factor (FF(t)). Variations in quantum efficiency (QE), capacitance–voltage (CV), and conductance–voltage (SV) can also be predicted using the simulation tool. Cells were stressed under AM1.5G, 1-sunlight, and open-circuit conditions at various temperatures.

To perform this simulation, we use individual layer parameters which are specifically referred to as Table 1 and Figure 1.

thumbnail Fig. 1

SCAPS 1D definition panel for CdS/CdTe solar cell.

Table 1

Individual layer parameters set in SCAPS environment.

3 Results and discussion

The ambient temperature influence on the CdS/CdTe solar cells performances through using the simulator SCAPS-1D. Figure 2 indicates the effect of ambient temperature on the characteristics J(V) of CdS/CdTe solar cells. We detected a small circuit current density (Jsc) as compared with the significant decrease in (Voc) open circuit voltage. (IV) measurements were obtained under AM1.5G, 1-sunlight for the temperatures 300 K, 340 K, and 360 K. As applied voltage will increase, current will increase.

Figure 3 illustrates the external quantum efficiency of the solar cell for several used temperatures. The external quantum efficiency of the cell has a wide-ranging characteristic for all usage temperatures. The small wavelengths from 300 nm to 340 nm agree with incidental photons with considerable energy. These photons participate more further in the overheating of the cell than to the construction of carriers expected to be collected. They provide weak QE because the amount of carriers is remained weak. On or after 340 nm the QE come to be significant.

It reaches the extreme of 90% for an incidental wavelength of 660 nm. The choice of processing steps was often dictated by economic reasons, using fast processing method with rapid throughput and good process yield of useful cells with similar performance in excess of 85% [9]. The range of collected carriers is maximum and the density of the short circuit current is maximum. till 810 nm the extent of injection of incidental wavelengths provides significant QE. From this value, it descents rapidly to be negated with λ = 850 nm.

On the other hand, we observe the QE is not affected by the temperature variants. For usage temperatures from 300 K to 360 K one can obtain the similar shapes.

Table 2 shows different CdS/CdTe solar cell performances with the temperature. They concern with the voltage coefficient, the short circuit current density, the fill factor, and the conversion efficiency with respect to temperature.

Thus, as of Table 2 results, it can see that conversion efficiency decreases due to the increase of temperature. Resulting Voc, Jsc, FF and efficiency are near 0.8 V, 24 (mA/cm2), 74% and 16%, respectively. The obtained results were in accordance with those of the literature [24]. The difference of performance where significant, but all were lying between 8% and 16% efficiency, a Voc between 0.500 and 0.860 V, a short circuit current between 16 and 26 mA/cm2, and a fill factor between 63% and 76% [9].

Figure 4 illustrations inversely proportional between the square of the capacitance and the voltage for the different usage temperatures considered. The decrease is closed to the previous characteristics where we note the decrease of the capacitance agreeing with the voltage. On the other hand, the influence of the temperature on the Mott-Schottky curves is a little noted by variants on the characteristics.

Figure 4 describes the CV characteristics of CdS/CdTe solar cell at usage temperature levels. By a way of the gate bias increases directly above a definite voltage, the capacitance value increases and saturates.

Figure 5 displays the variation of the capacitance vs the voltage for different usage temperatures. For an applied voltage going till 0.2 V, the capacitance of the cell show a discrepancy shortly with respect to the temperature. Away from 0.2 V we note characteristics that always change in the similar direction but according to different proportions. Certainly, the capacitance increases considerably and we found that more the usage temperature is significant more the capacitance is significant.

Certainly the conductance is the opposite of the resistance that's associated with the temperature, from in which the effect of the temperature at the conductance. Figure 6 offers us the profiles of the conductance of the carriers in line with the carried out voltage. We observe that voltages higher than 0.45 V growth the conductance that's measured beginning from the right-hand side of the cell provided via Figure 1. This conductance is likewise supported by using the increase of the use temperature. The selection of shunt resistances limitless with regards to the collection resistances explains the conduct of the conductance. We point out that the reference voltage standard is measured at the right-hand side in which the conductance is evaluated, while the implemented voltage is finished on the left. The resistance lowering with the growth in temperature, we observe a greater significant conductance for the highest use temperature.

thumbnail Fig. 2

Effect of temperature (red curve for 300 K, blue curve for 340 K, and green curve for 360 K) on VJ curve.

thumbnail Fig. 3

Temperature dependence on QE of CdS/CdTe.

Table 2

Temperature dependency of CdS/CdTe Solar cell performances.

thumbnail Fig. 4

Variation of the reverse of the square of the capacitance vs the voltage for different values of usage temperatures.

thumbnail Fig. 5

Capacitance–voltage curve representative the effect of temperature.

thumbnail Fig. 6

Variation of the generation of the minority carriers in conformity with the tension for different temperatures of usage.

4 Conclusions

The modeling of the CdS/CdTe became studied with the aid of the usage of SCAPS-1D to assess the temperature responsible for enhancing the efficiency of this solar cell. Finally at this study, we conclude:

  • The effect of the temperature on the capacitance–voltage and IV curves descriptions.

  • The influence of the using temperature on the variation of the capacitance of cell due to the voltage, is significant.

  • The evaluation of the Mott–Schottky curves for temperatures allows us to observe that the effect of the temperature on the Mott–Schottky curves is slightly mentioned and it seems weakly with the aid of variations at the characteristics.

  • The use temperature has a completely weak effect at the external quantum efficiency of the cell.

  • For all of the different using temperatures, we have got a maximum efficiency of 90% for an incidental wavelength of 660 nm and a wide beach of absorption.

Acknowledgments

The authors wish to thank Dr. M. Burgelman's group of Electronics and Information Systems (ELIS), University of Gent, for the SCAPS-1D program tool.

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Cite this article as: Abdel-baset H. Mekky, Influence of temperature on CdS/CdTe thin film solar cell, Eur. Phys. J. Appl. Phys. 87, 30101 (2019)

All Tables

Table 1

Individual layer parameters set in SCAPS environment.

Table 2

Temperature dependency of CdS/CdTe Solar cell performances.

All Figures

thumbnail Fig. 1

SCAPS 1D definition panel for CdS/CdTe solar cell.

In the text
thumbnail Fig. 2

Effect of temperature (red curve for 300 K, blue curve for 340 K, and green curve for 360 K) on VJ curve.

In the text
thumbnail Fig. 3

Temperature dependence on QE of CdS/CdTe.

In the text
thumbnail Fig. 4

Variation of the reverse of the square of the capacitance vs the voltage for different values of usage temperatures.

In the text
thumbnail Fig. 5

Capacitance–voltage curve representative the effect of temperature.

In the text
thumbnail Fig. 6

Variation of the generation of the minority carriers in conformity with the tension for different temperatures of usage.

In the text

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