Combination of Theoretical and Experimental Study*

We study the ground- and excited-state properties of Zn2Mo3O8 using first principles methods based on density functional theory and many body perturbation theory. We find that Zn2Mo3O8 is a indirect gap semiconductor, with a quasiparticle (optical) gap of 3.14 eV (2.34 eV). Our results are in good agreement with experimental data from UV-visible spectroscopy and spectroscopic ellipsometry. We show that the discrepancy between theoretical and experimental results can be attributed to finite temperature effects. The optical gap of this material makes it suitable for absorbing a significant fraction of solar radiation. This combined with piezoelectric response makes this material promising candidate for piezo-phototronics applications.