Photoluminescence of CVD-grown MoS2 modified by pH under aqueous solutions toward potential biological sensing
Photoluminescence of CVD-grown MoS2 modified by pH under aqueous solutions toward potential biological sensing
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DOI：
10.1088/2053-1583/ab712d
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发表时间：
2020-01
期刊：
影响因子：
5.5
通讯作者：
Takakazu Seki;T. Ihara;Y. Kanemitsu;Y. Hayamizu
中科院分区：
文献类型：
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作者：
Takakazu Seki;T. Ihara;Y. Kanemitsu;Y. Hayamizu
以二硫化钼（MoS2）为代表的过渡金属二硫化物（TMD）在生物传感领域具有广泛的应用前景。MoS2的半导体特性加上它的大表面积允许对外部环境的高灵敏度检测。虽然化学气相沉积（CVD）是一种很有前途的制备大质量MoS2的方法，但化学气相沉积（CVD）生长的MoS2在生理溶液下的光学性质尚不清楚。此外，对pH值对其光学性质的影响的了解仍然有限。本文利用光谱学和成像技术报道了它们的光致发光（PL）在水溶液条件下对溶液pH的响应。采用不同的Mo源和添加剂（MoS2、MoO2和NaCl）合成了MoS2。结果表明，钼源对PL响应的影响较大。由MoO2制成的MoS2对pH值的调制最高，而由MoS2制成的MoS2对pH值的调制没有显著的响应。此外，我们证明了UV/O3处理增强了ph敏感性。光电子能谱分析和x射线光电子能谱分析表明，光电子能谱对溶液pH的响应与MoS2的缺陷密度（S/Mo比）没有直接关系，而可能与其缺陷状态和初始载流子密度有关。这些发现将为优化合成条件、开发基于二硫化钼的光电生物传感器件提供实用指导。
Transition metal dichalcogenide (TMD) represented by molybdenum disulfide (MoS2) is a promising platform for versatile applications in biosensing. The semiconducting properties of MoS2 coupled with its large surface area allows for highly sensitive detection of external environments. Although chemical vapor deposition (CVD) is a promising method for synthesizing large and high quality MoS2, optical properties of CVD-grown MoS2 under physiological solution is not clear. Furthermore, understanding of the pH effect on its optical properties is still limited. Here, we report their photoluminescence (PL) responses to solution pH under aqueous condition by means of PL spectroscopy and imaging. MoS2 with different Mo sources and additive such as MoS2, MoO2 and NaCl were synthesized. It was found that the PL response was highly affected by the Mo sources. While MoS2 made from MoO2 showed the highest modulation of PL by solution pH, MoS2 made from MoS2 did not show significant response. Furthermore, we demonstrated enhanced pH-sensitivity by UV/O3 treatments. Spectral analysis on PL and x-ray photoelectron spectroscopy revealed that the PL responses to solution pH were not directly correlated to the defect density (S/Mo ratio) of MoS2, but likely correlated to its state of defects and initial carrier density. These findings will be a practical guideline to optimize synthesis condition toward developing MoS2-based optoelectronic biosensing devices.