New approach of both junction and back surface recombination velocities in a 3D modelling study of a polycrystalline silicon solar cell

¹ Laboratoire des Semiconducteurs et d'Énergie solaire, Département de Physique, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, BP 15 003 Dakar Fann, Senegal
² Section de Physique Appliquée, UFR de Sciences Appliquées et de Technologie, Université Gaston Berger, BP 234 Saint-Louis, Senegal
³ Centre National pour la Recherche Scientifique et Technique (CNRST), Ouagadougou, Burkina Faso

Corresponding author: gsissoko@yahoo.com

Received: 4 May 2007
Revised: 31 October 2007
Published online: 4 June 2008

Abstract

A 3D modelling is used to obtain the expression of excess minority carrier density in base region of a polycrystalline silicon solar cell. The concept of the junction recombination velocity S_f is used to quantify how excess carrier flow through the junction in actual operating conditions. The plot of the photocurrent density allowed study the influence of the grain boundary recombination velocity and grain size on both, the junction recombination velocity and on the back surface recombination velocity of an n⁺-p-p⁺ solar cell. This study pointed out the importance of the losses at the back side of solar cell. It's also show that the junction recombination velocity is more important for small grain size with large values of grain boundary recombination velocity.