Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2016)
    Energy Harvesting & Storage Tuesday Sessions
       Session EH-TuM

Paper EH-TuM12
Atomic Scale Understanding of the CdS/Cu(In,Ga)Se2 Interface in Alkali-incorporated Solar Cells

Tuesday, December 13, 2016, 11:40 am, Room Lehua

Session: Surfaces & Interfaces for Solar Cells and Solar Fuels
Presenter: Mowafak Al-Jassim, NREL, USA
Correspondent: Click to Email
Polycrystalline thin film technologies are rapidly evolving to be an important part of the solar energy portfolio and currently have about 10% of the photovoltaics market share. Cell efficiencies exceeding 22% have been reported for CIGS, which makes thin film solar cells competitive with wafer Si cells. However, this is still considerably lower than the theoretical efficiency limit. In this work we investigate carrier loss mechanisms in CIGS thin films associated with grain boundaries and interfaces. We combined scanning electron microscopy (SEM)-based cryogenic cathodoluminescence (CL) spectrum imaging and electron backscatter diffraction (EBSD) in order to map the spatial distribution of various atomic-level defects as a function of deposition and film processing. These investigations were complemented with atom probe tomography and high resolution STEM-EELS to study the chemical nature of the defects. In addition to investigating the structural and chemical properties of grain boundaries and interfaces in CIGS cells, considerable emphasis was placed on understanding the role of alkali post-deposition treatment in improving cell efficiency. These results will be presented and discussed.