Unravelling the early oxidation mechanism of zinc phosphide (Zn3P2) surfaces by adsorbed oxygen and water: a first-principles DFT-D3 investigation

Zinc phosphide (Zn₃P₂) is a novel earth-abundant photovoltaic material with a direct bandgap of 1.5 eV. Herein, the incipient oxidation mechanism of the (001), (101), and (110) Zn₃P₂ surfaces in the presence of oxygen and water, which severely limits the fabrication of efficient Zn₃P₂-based photovoltaics has been investigated in detail by means of dispersion-corrected density functional theory (DFT-D3) calculations. The fundamental aspects of the oxygen and water adsorption, including the initial adsorption geometries, adsorption energies, structural parameters, and electronic properties are presented and discussed. A chemical picture and origin of the initial steps of Zn₃P₂ are proposed through Bader population analyses.

Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 10 datasheets namely: Bulk-Zn₃P₂-strucure; DOS-bulk-Zn3P2-data; Adsorption-energies; Bader-charge-analyses; O2-ads-Zn3P2(001); O2-ads-Zn3P2(101); O2-ads-Zn3P2(110); H2O-ads-Zn3P2(001); H2O-ads-Zn3P2(101); and H2O-ads-Zn3P2(110), which provides information on the structural, binding energies, charge analyses, and optimized adsorption geometries of O2 and H2O molecules on the (001), (101), and (110) Zn3P2 surfaces. Data for the optimized structures for the bulk Zn₃P₂ and the surface+O2/H2O systems are available in CONTCAR format of the VASP simulation program. The CONTCAR files consist of lattice parameter and atomic positions and can be viewed using VESTA, and P4VASP software. The density of states (DOS) data for the bulk-Zn3P2are in 2 columns: the first column been the Energy (eV) and the second column been the intensity of the DOS (arb. units). This DOS data can be plotted using any plotting software, e.g., xmgrace, excel.

Research results based upon these data are published at https://doi.org/10.1039/C9CP03902C