Tin(II) selenide is an important binary IV-VI semiconductor compound with a wide range of potential applications (e.g., memory switching devices, infrared optoelectronic devices, and anode materials for rechargeable lithium batteries). Bulk SnSe has both an indirect band gap at 0.90 eV and a direct band gap at 1.30 eV. Owing to the quantum confinement effect, tunable band gaps of SnSe nanostructured materials (e.g., thin films and nanocrystals) have been demonstrated, which makes them capable of absorbing a major portion of solar energy. As an earth-abundant, environmentally benign, and chemically stable material, SnSe is placed among the most promising candidates for solar cells.
We present herein a facile, solution-phase synthetic approach to colloidal SnSe nanowires, which have a mean diameter of approximately 20.8 nm, lengths tunable from hundreds of nanometers to tens of micrometers, and more importantly, a monocrystalline structure. Their optical and electric properties are examined by UV/Vis/NIR spectroscopy, cyclic voltammetry (CV), and transient photocurrent measurements, and a quantum confinement effect is clearly revealed.
These results may improve our understanding of their basic optical and electrical properties and may also aid their utility as building block in various applications, such as photovoltaic devices. The hybrid solar cells based on a blend of the long SnSe nanowires and P3HT exhibited PCEs of 0.01% under AM 1.5 sun. Further studies for enhancing the device performance are under way.
Solution-Phase Synthesis and Characterization of Single-Crystalline SnSe Nanowires
Sheng Liu, Xiaoyang Guo, Mingrun Li, Wen-Hua Zhang*, Xingyuan Liu*, Can Li*
Angew. Chem. Int. Ed.,2011, DOI:10.1002/anie.201105614.