Synthesis, structure and photoelectric properties of selenide composites with in situ constructed Sb2Se3/NaSbSe2 heterojunction

Abstract Inorganic semiconductor heterojunctions have attracted extensive attention for technological applications owing to interface phenomena. In this work, selenide composites with in situ constructed Sb2Se3/NaSbSe2 heterojunctions with similar band gap width have been synthesized by conventional melt-quenching method. The microstructure and photoelectric properties of the composites were investigated at different NaSbSe2 contents. The study revealed that NaSbSe2 content has direct influences on the photoelectric performance of the composites by modifying the heterojunction size and the grain boundary resistance, as evidenced by scanning electron microscopy and impedance spectroscopy, respectively. The photocurrent density of Sb2Se3 with 2.5 and 5 mol% NaSbSe2 was approximately 180 times larger than that of the pure Sb2Se3 at a bias voltage of -1.5 V and under an illumination of 7 mW/cm2, due to an effective separation of photogenerated carriers through the interface electric field. Additionally, the composites exhibited an excellent stability even in 0.5 M LiClO4 aqueous electrolyte.