Defect Characterization of Cu2ZnSnSe4 Thin Film Solar Cells Using Advanced Microscopic Techniques

Abstract

Thin film chalcogenide solar cells have been utilized in a broad range of application for their tunable direct bandgap and high efficiency. In this work, we performeda novel fabrication and multiple high-resolution characterizations of Cu2ZnSnSe4(CZTSe) solar cells, which is believed to be a better candidate compared to well-developed CuInxGa(1-x)Se2(CIGS)for its earth-abundant contents. The fabrication is based on nanoparticle precursor production by liquid-phase pulsed laser ablation, electrophoretic deposition of precursor thin film under ambient condition, and selenization. Such non-vacuum fabrication has the advantage of low cost and minimum impact on the environment. By studying the CZTSe and CIGS fabricated in the above methods using techniques including Raman integrated scanning probe microscope, electron holography, scanning transmission electron microscopy and in-situ transmission electron microscopy. We discoveredthe origin of the performance limit of the CZTSe compared to CIGS as well as the defect of our non-vacuum fabrication methods. The presented results, including the characterization methods, create a novel way to correlate the solar cell performance with the microstructure in a nanometer scale. It opens up the possibility for developing high performance solar cell devices from the prospective of nanostructure and defect engineering.