Fabrication of flexible and freestanding zinc chalcogenide single layers

Abstract

Inorganic graphene analogues (IGAs) are a conceptually new class of materials with attractive applications in next-generation flexible and transparent nanodevices. However, their species are only limited to layered compounds, and the difficulty in extension to nonlayered compounds hampers their widespread applicability. Here we report the fabrication of large-area freestanding single layers of non-layered Znse with four-atomic thickness, using a strategy involving a lamellar hybrid intermediate. Their surface distortion, revealed by means of synchrotron radiation X-ray absorption fine structure spectroscopy, is shown to give rise to a unique electronic structure and an excellent structural stability, thus determining an enhanced solar water splitting efficiency and photostability. The Znse single layers exhibit a photocurrent density of 2.14 mA cm − 2 at 0.72 V versus Ag/AgCl under 300 W Xe lamp irradiation, 195 times higher than that of bulk counterpart. This work opens the door for extending atomically thick IGAs to non-layered compounds and holds promise for a wealth of innovative applications.

Aligned Fe2TiO5-containing nanotube arrays with low onset potential for visible-light water oxidation

“…In addition, the Fe 2 TiO 5 -containing photoanode combines the advantages of substantial optical absorption of narrow-bandgap Fe 2 O 3 and a low external bias of wide-bandgap TiO 2 to drive solar water oxidation. Together with the intrinsic merits of anticorrosion and cheapness of transition metal oxides, this composite system has shown its great potential as a practical photoelectrochemical material 28 .…”

X-ray absorption fine structure spectroscopy in nanomaterials

“…Our group have conducted a series of studies for various nanosheets materials [83][84][85][86][87][88], and EXAFS has played important roles in determining their structure and understanding their unique stability.…”

“…The first example is the study on the large-area freestanding ZnSe single layers with four-atomic thickness [83], which were fabricated by virtue of lamellar hybrid (Zn 2 Se 2 )(pa) (pa stands for n-propylamine) intermediate. The hybrid ZnSe-pa single layers were initially exfoliated and then pa molecules were removed by heat treatment at 140°C for 2 h. To interpret the stability of the ZnSe single layers, EXAFS data at both Zn and Se K-edges were measured (Figs 17a and b).…”

Stable ultra-thin CdTe crystal: a robust direct gap semiconductor

“…27 Furthermore, using a lamellar hybrid intermediate, large-area, free-standing, single-layers of ZnSe were fabricated. 28 Single-layers of ZnSe-pa (pa stands for n-propylamine) were exfoliated from a lamellar hybrid (Zn 2 Se 2 )(pa) intermediate.…”