Metastable Tetragonal Cu2Se Hyperbranched Structures: Large‐Scale Preparation and Tunable Electrical and Optical Response Regulated by Phase Conversion |
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Authors: | Dr. Jinbao Zhu Qiuyang Li Liangfei Bai Yongfu Sun Min Zhou Prof. Yi Xie |
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Affiliation: | Department of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (P. R. China), Fax: (+86)?551‐3603987 |
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Abstract: | Despite the promising applications of copper selenide nanoparticles, an in‐depth elucidation of the inherent properties of tetragonal Cu2Se (β‐Cu2Se) has not been performed because of the lack of a facile synthesis on the nanoscale and an energy‐intensive strategy is usually employed. In this work, a facile wet‐chemical strategy, employing HCOOH as reducing agent, has been developed to access single‐crystalline metastable β‐Cu2Se hyperbranched architectures for the first time. The process avoids hazardous chemistry and high temperatures, and thus opens up a facile approach to the large‐scale low‐cost preparation of metastable β‐Cu2Se hyperbranched architectures. A possible growth mechanism to explain the formation of the β‐Cu2Se dendritic morphology has been proposed based on time‐dependent shape evolution. Further investigations revealed that the metastable β‐Cu2Se can convert into the thermodynamically more stable cubic α‐Cu2?xSe maintaining the dendritic morphology. An increase in electrical conductivity and a tunable optical response were observed under ambient conditions. This behavior can be explained by the oxidation of the surface of the β‐Cu2Se hyperbranched structures, ultimately leading to solid‐state phase conversion from β‐Cu2Se into superionic conductor α‐Cu1.8Se, which has potential applications in energy‐related devices and sensors. |
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Keywords: | absorbance conducting materials copper nanostructures selenium |
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