Direct utilization of solar energy by photovoltaics and photo-catalysis requires semiconducting materials with a suitable band gap and appropriate valence and conduction band positions. Electronic band structures therefore play a crucial role in solar-energy conversion. Kohn-Sham density functional theory (KS-DFT) in the local or semilocal approximations (LDA/GGA) has serious difficulty in describing electronic properties of extended systems. In this work, we apply many-body perturbation theory in the GW approximation, currently the most accurate first-principles approach for electronic band structures of extended systems, to investigate electronic properties of two types of materials, early transition metal dichalcogenides MX2 (M=Zr, Hf, Mo, W, and X=S and Se) and alkali tantalates (ATaO3, A=Li, Na and K), which are promising for use in solar energy conversion. We also calculate absolute band positions with respect to the vacuum level by combining KS-DFT calculations in the slab model and GW quasi-particle corrections.

Electronic band structures of materials for solar energy conversion from the <i>GW</i> perspective

244th National Meeting (2012)

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Electronic band structures of materials for solar energy conversion from the GW perspective