Li Anran, Yu Jian, Lin Jie, Chen Mo, Wang Xiaotian, Guo Lin
Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, School of Chemistry, Beihang University, Beijing 100191, P. R. China.
Cixi Institute of Biomedical Engineering, Chinese Academy of Science (CAS) Key Laboratory of Magnetic Materials and Devices and Key Laboratory of Additive Manufacturing Materials of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 1219 ZhongGuan West Road, Ningbo 315201, P. R. China.
J Phys Chem Lett. 2020 Mar 5;11(5):1859-1866. doi: 10.1021/acs.jpclett.0c00187. Epub 2020 Feb 24.
Enriching the electronic density of states (DOS) of semiconductors is the key to promoting charge transfer (CT) and achieving a large surface-enhanced Raman scattering (SERS) enhancement. Metal hydroxide semiconductors are anticipated to exhibit DOS that are higher than those of metal oxide because of their abundant O atoms; however, their SERS activity has not been verified. Here, combining density functional theory and experiments, we report a SERS sensitivity of amorphous Zn(OH) [a-Zn(OH)] that is much higher than that of amorphous ZnO (a-ZnO), ascribed to the abundant O atoms and hence enriched O 2p state density near the Fermi level in a-Zn(OH), which gives rise to higher CT probabilities. Moreover, we find a-Zn(OH) exhibits significant advantages in energy-level matching over a-ZnO for efficient photoinduced CT via strong vibronic coupling, ascribed to the upshifted valence band maximum and the narrower band gap of a-Zn(OH). Via the synthesis of a-Zn(OH) nanocages, an ultrahigh enhancement factor of 1.29 × 10 is obtained in semiconductor-based SERS.
提高半导体的电子态密度（DOS）是促进电荷转移（CT）并实现大幅表面增强拉曼散射（SERS）增强的关键。由于金属氢氧化物半导体含有丰富的氧原子，预计其表现出比金属氧化物更高的DOS；然而，它们的SERS活性尚未得到验证。在此，结合密度泛函理论和实验，我们报道了非晶态Zn(OH) [a-Zn(OH)]的SERS灵敏度远高于非晶态ZnO（a-ZnO），这归因于a-Zn(OH)中丰富的氧原子以及费米能级附近富集的O 2p态密度，从而产生更高的CT概率。此外，我们发现a-Zn(OH)通过强振动耦合在能级匹配方面相对于a-ZnO具有显著优势，有利于高效的光致CT，这归因于a-Zn(OH)价带最大值上移和带隙变窄。通过合成a-Zn(OH)纳米笼，在基于半导体的SERS中获得了1.29×10的超高增强因子。
