Optical and dielectric studies of gel grown α-hopeite single crystal

The impact of physiological buffer solutions on zinc oxide nanostructures: zinc phosphate conversion

“…We would like to note at this point that, despite our estimations of the bandgap energy of the Zn3(PO4)2•xH2O being identical for the commercial powders and for the samples converted through this study, in the literature this value remains controversial and under debate, with different investigations pointing to seemingly contradicting results. Nevertheless, values between ~3.2 eV and 3.7 eV have been proposed [59,74,75]. These contradictions may be mainly because the differences in the hydrate states (xH2O) can influence the intermolecular interactions and the crystalline arrangement, which, in turn, affects several material properties, including the electronic band structure and consequently the bandgap energy [75,76].…”

“…In the latter case, the α-phase is frequently the dominant structure, although a mixture of α-, β-, and γ-hopeite occurs in many cases [59]. For instance, Mangalam et al [74] reported a (direct) bandgap energy of 3.25 eV for single crystals synthesized by a single diffusion gel growth technique. On the other hand, Parhi et al [59] were able to synthesise the same phase by a metathetic reaction at RT, obtaining a single-phase material with a (direct) bandgap value of ca.…”