Design of ternary alkaline-earth metal Sn(ii) oxides with potential good p-type conductivity

Abstract

Oxides with good p-type conductivity have been long sought after to achieve high performance all-oxide optoelectronic devices. Divalent Sn(II) based oxides are promising candidates because of their rather dispersive upper valence bands caused by the Sn-5s/O-2p anti-bonding hybridization. There are so far few known Sn(II) oxides being p-type conductive suitable for device applications. Here, we present via first-principles global optimization structure searches a material design study for a hitherto unexplored Sn(II)-based system, ternary alkaline-earth metal Sn(II) oxides in the stoichiometry of MSn2O3 (M = Mg, Ca, Sr, Ba). We identify two stable compounds of SrSn2O3 and BaSn2O3, which can be stabilized by Sn-rich conditions in phase stability diagrams. Their structures follow the Zintl behaviour and consist of basic structural motifs of SnO3 tetrahedra. Unexpectedly they show distinct electronic properties with band gaps ranging from 1.90 (BaSn2O3) to 3.15 (SrSn2O3) eV, and hole effective masses ranging from 0.87 (BaSn2O3) to above 6.0 (SrSn2O3) m0. Further exploration of metastable phases indicates a wide tunability of electronic properties controlled by the details of the bonding between the basic structural motifs. This suggests further exploration of alkaline-earth metal Sn(II) oxides for potential applications requiring good p-type conductivity such as transparent conductors and photovoltaic absorbers.

Transparent conducting materials discovery using high-throughput computing

“…The study clearly indicates the difficulty to find high-mobility p-type oxides due to the 42,99 Further computational exploration of the Sn 2+ and Pb 2+ chemistries was also performed by Singh et al focusing on alkali-earth and phosphates. [100][101][102] Bhatia et al 103 extended this HT screening to quaternary oxides. The screening identified Ba 2 BiTaO 6 as a p-type TCO candidate.…”

Cu–In Halide Perovskite Solar Absorbers

“…The more rigorous stability filter, involves examination of all other decomposition channels into various combinations of competing phases. 67,68 Fig . 2 shows the calculated primary stability metric ΔH dec plotted vs calculated band gaps E g (all being direct) for the candidate CIHPs (the explicit data are listed in Supplementary Table S1).…”

“…A possible factor responsible for this inconsistency is the reliability of evaluation of t and μ in current double-perovskite system containing mixed cations at the octahedral site. More precise thermodynamic stability analysis of the primarily stable solar CIHPs: We perform thorough evaluation of thermodynamic stability via the phase stability diagram analysis 67,68 (as described in Supplementary Sec. I) for the 13 CIHPs passing the above initial screening.…”

Perovskite-Inspired Photovoltaic Materials: Toward Best Practices in Materials Characterization and Calculations

“…1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Polymorphism Knowing the atomic structure of a material can be challenging because many compounds exhibit polymorphism, in which the materials can exist in different crystal structures. 191,192 It is important that the relative energies of the polymorphs are accurately described by the DFT exchange-correlation functionals, so that the correct ground-state structure is used for property predictions. DFT is generally considered to accurately calculate the total energy but can, in some cases, fail to predict the correct polymorph.…”