Share Email Print
cover

Proceedings Paper

Lambertian back reflector in Cu(InGa)Se2 solar cell: optical modeling and characterization
Author(s): Nir Dahan; Zacharie Jehl; Jean-François Guillemoles; Daniel Lincot; Negar Naghavi; Jean-Jacques Greffet
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

In the past years, reducing the thickness of the absorber layer in CIGS-based solar cells has become a key issue to reduce the global Indium consumption and thus increased its competitiveness. As the absorber thickness is reduced, less photons are absorbed and consequently the efficiency decreases. It is well known that scattering light in the absorbing layer increases the effective optical length, which results in enhanced absorption. In this study, we have deposited a transparent conductive oxide as a back contact to the cell with a white paint on the rear surface to diffuse the light back to the cell. A proof of concept device is realized and optically characterized. Modeling scattering by rough surfaces can be done by brute force numerical simulations but does not provide a physical insight in the absorption mechanisms. In our approach, we regard the collimated solar light and its specular reection/transmission as coherent. On an irregular surface, part of the collimated light is scattered in other directions. To model this diffuse light, we adopt the formalism of the radiative transfer equation, which is an energy transport equation. Thus, interference effects are accounted for only in the coherent part. A special attention is dedicated to preserving reciprocity and energy conservation on the interface. It is seen that most of the absorption near the energy bandgap of CIGS is due to the diffuse light and that this approach can yield very significant photocurrent gains below 500nm absorber thickness.

Paper Details

Date Published: 25 March 2013
PDF: 8 pages
Proc. SPIE 8620, Physics, Simulation, and Photonic Engineering of Photovoltaic Devices II, 862019 (25 March 2013); doi: 10.1117/12.2003968
Show Author Affiliations
Nir Dahan, Institut de Recherche et Développement sur l'Energie Photovoltaïque, CNRS, Chimie Paristech (France)
Lab. Charles Fabry, CNRS, Univ. Paris-Sud (France)
Zacharie Jehl, Institut de Recherche et Développement sur l'Energie Photovoltaïque, CNRS, Chimie Paristech (France)
Jean-François Guillemoles, Institut de Recherche et Développement sur l'Energie Photovoltaïque, CNRS, Chimie Paristech (France)
Daniel Lincot, Institut de Recherche et Développement sur l'Energie Photovoltaïque, CNRS, Chimie Paristech (France)
Negar Naghavi, Institut de Recherche et Développement sur l'Energie Photovoltaïque, CNRS, Chimie Paristech (France)
Jean-Jacques Greffet, Lab. Charles Fabry, CNRS, Univ. Paris-Sud (France)


Published in SPIE Proceedings Vol. 8620:
Physics, Simulation, and Photonic Engineering of Photovoltaic Devices II
Alexandre Freundlich; Jean-Francois Guillemoles, Editor(s)

© SPIE. Terms of Use
Back to Top