A one-pot synthesis of novel hierarchical flower-like Cu7.2S2Se2 nanocrystals was developed based on the direct metal surface elemental reaction (DMSER) method. This new room temperature synthesis is an economic and environmentally friendly soft chemical approach. The prepared Cu7.2S2Se2 nanocrystals uniformly cover the surface of the Cu substrates. The mechanism of formation was investigated by observing the materials produced from changing the reaction time, the molar ratio of Na2S to elemental selenium, and the volume of solvent. The crystal structure, surface morphologies and light absorption properties were collected by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-visible spectroscopy. The results show that the as-prepared ternary nanocrystals are face-centered cubic and have an optical bandgap of 1.58 eV, which is ideal for potential solar cell applications. Transient photovoltage spectroscopy (TPV) was used to evaluate the photovoltaic performance of pure Cu7.2S2Se2 nanocrystalline powder as well as in-situ generated Cu7.2S2Se2/ZnO heterojunctions. The current work offers a novel and simple approach for preparing ternary chalcogenide semiconductors for photoelectric and photocatalytic applications. (C) 2017 Elsevier B.V. All rights reserved.