Optimization of the Properties of the Back Surface Field of a Cu(In,Ga)Se₂ Thin Film Solar Cell

Alain Kassine Ehemba^1, , Mouhamadou Mamour Socé¹, Jean Jude Domingo¹, Salif Cisse¹ and Moustapha Dieng¹

¹Laboratory of Semiconductors and Solar Energy, Physics Department, Faculty of Science and Technology, University Cheikh Anta Diop, Dakar

Cite this paper:
Alain Kassine Ehemba, Mouhamadou Mamour Socé, Jean Jude Domingo, Salif Cisse and Moustapha Dieng. Optimization of the Properties of the Back Surface Field of a Cu(In,Ga)Se₂ Thin Film Solar Cell. American Journal of Energy Research. 2017; 5(2):57-62. doi: 10.12691/ajer-5-2-5

Abstract

The use of the back surface field BSF within the thin film cells isn't elaborated in a current state of research. In this article we try to adapt it to the Cu(In,Ga)Se₂ thin film solar cells. The theoretical study is based on the resolution in one dimension of the equations which govern the behaviour of a photovoltaic cell. The spectrum used is the AM 1.5. The experimental method takes into account all physical phenomena which happen in the solar cell. The comparison of the macroscopic electric parameters of the two cells with BSF and without BSF enabled us to obtain a conversion efficiency of 21.95% for the cell with BSF whereas it is equal to 20.78% for the cell without BSF. The use of the BSF presents a broad maximum absorption band which extends from 0.4µm to 1µm through the study of the quantum efficiency of the cell. The spectral response of the layer reaches a value of 0.7A.W^-1 for an incidental wavelength of approximately 1000nm which corresponds to the gap of the absorber of the solar cell of 1.2eV. The improvement of the thickness of the p+ CIGS up-doped, indicates an optimal thickness of 0.5.µm. We find for this thickness an open circuit voltage of 0.71V, a short-circuit current density of 37.409mA.cm^-2 and a conversion efficiency of 21.95%. The optimization of the doping concentration acceptors of the p+ CIGS, shows that the optimal concentration corresponds to 10E18cm^-3. We find with this acceptors density an open circuit voltage of 0.69V, a short circuit current density of 37.40mA.cm^-2 and a conversion efficiency of 21.74%.

Keywords:
thin film Back Surface Field Cu(InGa)Se₂ electric parameters

This work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

References:

[1]	Available: http://www.lechodusolaire.fr/cellules-solaires-cigs-226-de-rendement-de-conversion-zsw/. [Accessed Sept. 18, 2017]
[2]	Alain Kassine Ehemba, Ibrahima Wade, Mouhamadou Mamour Soce, Djimba Niane, Moustapha Dieng, “Study of the consequences of the front external reflection on the electric parameters of a thin film Cu(In,Ga)Se2 solar cell”, Research Journal of Engineering Sciences, Vol 05, Issue 10, pp. 01-06, 2016.
[3]	Demba Diallo, Alain Kassine Ehemba, Amsata Ndiaye, Mouhamadou Mamour Soce, Moustapha Dieng, “The influence of the thickness of the CdS emitter layer on the performance of a CIGS solar cell with acceptor defects”, International Journal of Engineering and Applied Sciences, Vol. 4, Issue 1, pp. 1-4, 2017.
[4]	Vinh Ai Daoa, Jongkyu Heoa, Hyungwook Choia, Yongkuk Kima, Seungman Parka, Sungwook Junga, Nariangadu Lakshminarayan, Junsin Yia,c, “ Simulation and study of the influence of the buffer intrinsic layer, back-surface field, densities of interface defects, resistivity of p-type silicon substrate and transparent conductive oxide on heterojunction with intrinsic thin-layer (HIT) solar cell”, Solar Energy, Vol. 84, pp. 777-783, 2010.
[5]	“Simplified fabrication of back surface electric field silicon cells and novel characteristics of such cells”, in Ninth Photovoltaic Specialists Conference sponsored by the Institute of Electrical arid Electronics Engineers Silver Spring, Joseph Mandelkorn and John H. Lamneck.
[6]	Alain Kassine Ehemba, Moustapha Dieng, Demba Diallo, Gerome Sambou, “Influence of the donor doping density in CdS and Zn(O,S) buffer layers on the external quantum efficiency of Cu(In,Ga)Se2 thin film solar cell”, International Journal of Engineering Trends and Technology, Vol. 28, Issue 6, pp. 280-286, 2015.