2017-Sustainable Industrial Processing Summit
SIPS 2017 Volume 8: Surfaces and Interfaces(SISAM), Composite, Ceramic and Nanomaterials
| Editors: | Kongoli F, Braems I, Demange V, Dubois JM, Pech-Canul M, Patino CL, Fumio O |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2017 |
| Pages: | 249 pages |
| ISBN: | 978-1-987820-75-1 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Thin-film Solar Cell Based on Cu1-xGaxSe2: The X-dependent Chemical Properties of the CuIn1-xGaxSe2 Interfaces
Isabelle Braems1; Polyxeni Tsoulka2; Nicolas Barreau3;1IMN-CNRS, Nantes Cedex, France; 2IMN, Nantes Cedex 3, France; 3UNIVERSITE DE NANTES, IMN, Nantes, France;
Type of Paper: Regular
Id Paper: 318
Topic: 42
Abstract:
A solar cell is a device that converts a solar energy into an electric current. Studying the properties of the absorber layer is a key point to optimize its conversion efficiency. In this study, we focus on polycrystalline CuIn1-xGaxSe2 (CIGSe), which is one of the most promising absorber layers for solarcells. So far, best labscale energy conversion efficiencies are achieved for x = [Ga]/([Ga]+[In]) ĦO0.3, while the theoretical x-dependent cell efficiency curve predicts better performances for x ĦO0.75. One possible explanation is that Grain Boundaries (GBs) play a specific role as a function of x. We suggest 2 possible phenomena that can occur at the CIGSe GBs: first, The interface and the grain interior compositions differ, and the nature of the predominant species at the interface varies with x. This is consistent with i) recent results obtained by APT (Atom Probe Tomography), and ii) our simple theoretical-based model of segregation driving forces that combine ab initio and statistical thermodynamics. Secondly, a detrimental solid solution can accumulate within the GBs. Our XRD, RAMAN and EDS analyses demonstrate a different behavior of a Cu-rich compound at low and high Ga-ratio. The nature of the accumulated species or compound at the interface can be detrimental or beneficial for the solar cell efficiency. Hence, in this contribution we discuss both experimentally and theoretically these two scenarios.