An Intermediate Band Material K2CdSnSe4 and Its Visible‐Light Photocatalytic Activity

Abstract

AbstractIntermediate bands (IBs) can significantly extend the absorption range of solar absorbers. Here, an intermediate band material K2CdSnSe4 was synthesized via a urea flux method at 220 °C. The structure features [CdSnSe4]2‐ one‐dimensional chains, which were built up by [CdSe4]6‐ and [SnSe4]4‐ tetrahedra via edge sharing. Optical measurements indicate that the as‐synthesized K2CdSnSe4 compound has typical multi‐absorption characters with an absorption edge at 1.63 eV and an absorption peak around 398 nm (3.1 eV). First‐principles calculation results, which are perfectly consistent with the experimental results, show that the intermediate bands mainly consist of Sn‐5 s and Se‐4p orbitals. Photoresponse was observed under visible light illumination with a photocurrent density of 217 μA⋅cm−2 at 1 V. Methyl orange (MO) was used as model pollutant for photodegradation test. About 99 % of MO (10 mg⋅L−1) was removed after 4 h under visible light illumination using K2CdSnSe4 powder (1 g⋅L−1) as photocatalyst, which is better than that of C3N4 (∼ 45 % at 240 min).