He Xin, Wang Yuechao, Gao Cai-Yan, Jiang Hong, Zhao Liang
The Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education) , Department of Chemistry , Tsinghua University , Beijing 100084 , China . Email:
Beijing National Laboratory for Molecular Sciences , State Key Laboratory of Rare Earth Materials Chemistry and Applications , Institute of Theoretical and Computational Chemistry , College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China.
Chem Sci. 2015 Jan 1;6(1):654-658. doi: 10.1039/c4sc01884b. Epub 2014 Sep 11.
We report herein a new nanoparticlization process for the bulk-to-nano transformation of AgS by incorporating both top-down and bottom-up approaches. Bulk AgS was dissolved in solution with the assistance of a macrocyclic ligand, hexamethylazacalix[6]pyridine (), to produce polynuclear silver sulfide cluster aggregates. All Ag-S cluster aggregates obtained in three crystalline complexes were protected by macrocycles. Removing the protective macrocycles by protonation led to the generation of unconventional Ag-S nanoparticles with a large energy gap. Theoretical calculations by a hybrid DFT method demonstrated that the silver sulfide clusters with high Ag/S ratio exhibited more localized HOMO-LUMO orbitals, which consequently enlarged their band gap energies. These experimental and theoretical studies broaden our understanding of the fabrication of nanomaterials by virtue of the advantages of both bottom-up and top-down methods and meanwhile provide a viable means of adjusting the band gap of binary nanomaterials independent of their size.
我们在此报告一种通过结合自上而下和自下而上的方法，实现硫化银从块状到纳米转变的新型纳米颗粒化过程。块状硫化银在大环配体六甲基氮杂杯[6]吡啶（）的辅助下溶解于溶液中，以生成多核硫化银簇聚集体。在三种晶体配合物中获得的所有硫化银簇聚集体都受到大环的保护。通过质子化去除保护性大环会导致生成具有大能隙的非常规硫化银纳米颗粒。采用混合密度泛函理论方法进行的理论计算表明，具有高银/硫比的硫化银簇表现出更多局域化的最高占据分子轨道-最低未占分子轨道，从而扩大了它们的带隙能量。这些实验和理论研究借助自下而上和自上而下方法的优势，拓宽了我们对纳米材料制备的理解，同时提供了一种独立于尺寸来调节二元纳米材料带隙的可行方法。
