Li Changzheng, Yue Yanan
School of Power and Mechanical Engineering, Wuhan University, Wuhan, Hubei 430072, People's Republic of China.
Nanotechnology. 2014 Oct 31;25(43):435703. doi: 10.1088/0957-4484/25/43/435703. Epub 2014 Oct 9.
This paper reports a comprehensive study of temperature dependence of fluorescence spectroscopy of graphene quantum dots at different excitation wavelengths. Very significant (more than 50%) and similar decrease of normalized spectrum intensity is observed within temperature range less than 80 °C for excitation wavelengths of 310 nm, 340 nm and 365 nm. Besides, the temperature dependence of the red-shift of spectrum peak shows different wavelength dependence characteristic with coefficient as high as 0.062 nm K(-1) for the same temperature range, which gives us a hint about selecting the right excitation wavelength by compromising the excitation efficiency for fluorescence intensity and the temperature coefficient for peak shift in thermal applications. Temperature dependence of peak width is in a weakly linear relationship with a coefficient of 0.026 nm K(-1). Regarding the excellent stability and reversibility during thermal measurement, graphene quantum dot is a good candidate for the implementation in the nanoscale thermometry, especially in the bio-thermal field considering its superior biocompatibility and low cytotoxicity.
本文报道了在不同激发波长下对石墨烯量子点荧光光谱温度依赖性的全面研究。对于310nm、340nm和365nm的激发波长，在低于80°C的温度范围内观察到归一化光谱强度非常显著（超过50%）且相似的下降。此外，光谱峰红移的温度依赖性呈现出不同的波长依赖性特征，在相同温度范围内系数高达0.062nm K⁻¹，这为我们在热应用中通过兼顾荧光强度的激发效率和峰移的温度系数来选择合适的激发波长提供了线索。峰宽的温度依赖性呈弱线性关系，系数为0.026nm K⁻¹。鉴于热测量过程中具有出色的稳定性和可逆性，石墨烯量子点是纳米级温度测量应用的良好候选材料，特别是考虑到其优异的生物相容性和低细胞毒性，在生物热领域更是如此。
