Passivation strategies for photovoltaic devices based on chalcogenide and nitride

Abstract

Currently, leading thin film solar cell technologies of CdTe, Cu(In,Ga) $Se_2$ (CIGS), and inorganic-organic hybrid perovskites have demonstrated record efficiencies above 22 %. In spite of such remarkable advancement in photovoltaic (PV) performance, issues with toxicity (Cd), scarcity (Te and In), and stability (perovskite) of the constituent elements still remain unsolved. To meet the commercial demands in PV technologies, earth-abundant and low-toxic chalcogenides such as $Cu_2ZnSn (S,Se)_4$ (CZTSSe) or $Sb_2Se_3$ have shown promising potential, yet exhibiting low efficiencies below 13 %. In this thesis, we investigate interface and defects passivation strategies in each solar cell technologies, respectively, to improve open-circuit voltage and efficiencies. Also, an emerging ternary nitride ($MgZrN_x$) will be discussed with tuning the material properties via hydrogen and oxygen induced passivation for PV application.