A theoretical study on the pure-phase stability of complex solar absorber materials

ORAL

Abstract

To make solar energy competitive with fossil fuels, sustainable and cost effective solar absorber materials are needed. In this regards, we are particularly interested in multi-cation oxide/sulfide materials as they present flexible pathways to tune their electronic and optical properties. Once a material is selected, the primary challenge is to predict whether the material or the material with preferred doping can be synthesized as pure-phase in thermodynamic equilibrium conditions. We will present density functional theory (DFT) studies on two such examples for solar absorber materials: (i) Cu$_{\mathrm{2}}$ZnSnS(Se) (CZTS) and (ii) Bi$_{\mathrm{2}}$Ti$_{\mathrm{2}}$O$_{\mathrm{7}}$ (BTO).$_{\mathrm{\thinspace }}$We'll fist show from the chemical potential landscape analysis that the formation of stoichiometric CZTS is practically impossible under thermodynamic equilibrium condition. Our study justifies the experimental growth conditions of CZTS (Zn rich and Cu-poor) for higher solar-to-current conversion efficiency. Growth condition for p-type CZTS and suitable reaction pathways will be presented. In the second example, a resent experiment showed that a transition metal such as Fe inclusion can enhanced photo-current of bismuth titanate (Bi$_{\mathrm{2}}$Ti$_{\mathrm{2}}$O$_{\mathrm{7}})$ up to an impurity concentration of \textasciitilde 1{\%}. Beyond this impurity concentration the photocurrent decreased due to the formation of Fe$_{\mathrm{2}}$O$_{\mathrm{3}}$ phase. Our theoretical study predicted the doping configurations and suitable chemical potential ranges to avoid formation of the Fe$_{\mathrm{2}}$O$_{\mathrm{3}}$ phase in Fe- doped BTO in order to increase the photo-current.

–

Authors

  • Muhammad N. Huda

    Deartment of Physics, University of Texas, Arlington

  • Arthur Sweeney

    Lee College, Baytown, TX, Lamar University, University of Texas at Arlington, Angelo State University, Rice University, Texas State University, College of William and Mary and National Institute of Aerospace, Nanyang Technological University, China Jiliang University, Baylor University, Louisiana State University, College of William and Mary, University of Oklahoma, University of Texas at Dallas, Univ of Texas, Austin, Texas State Univ-San Marcos, University of Cambridge, University of Texas at Austin, Indiana University - Bloomington, Lamar Univiversity, University of Cincinnati, Deartment of Physics, University of Texas, Arlington, Texas A&M University, College Station, University of Texas - Dallas, University of Dallas

  • Arthur Sweeney

    Lee College, Baytown, TX, Lamar University, University of Texas at Arlington, Angelo State University, Rice University, Texas State University, College of William and Mary and National Institute of Aerospace, Nanyang Technological University, China Jiliang University, Baylor University, Louisiana State University, College of William and Mary, University of Oklahoma, University of Texas at Dallas, Univ of Texas, Austin, Texas State Univ-San Marcos, University of Cambridge, University of Texas at Austin, Indiana University - Bloomington, Lamar Univiversity, University of Cincinnati, Deartment of Physics, University of Texas, Arlington, Texas A&M University, College Station, University of Texas - Dallas, University of Dallas