热处理对金纳米棒光学性能的影响

Significance of heat treatment on optical properties of gold nanorods

采用种子生长法合成了GNRs,并对其进行了不同温度的热处理。通过TEM、XRD、UV-vis等手段分析了热处理对金纳米棒的形貌、尺寸及光学性能的影响规律。结果显示:随着对GNRs的热处理温度升高,其LSPR发生蓝移,并且LSPR的半峰全宽(FWHM)明显减小,产生该现象的原因通过探究平均长径比为3.31、4.38、4.52的GNRs在110℃下保温不同时间后的LSPR的变化情况得出:GNRs轴向末端的十六烷基三甲基溴化铵(CTAB)相比侧面状态不稳定,使得高温下该处金原子更易脱落导致长度减小明显,进而造成长径比减小最终导致LSPR蓝移和窄化现象。

GNRs were synthesized by seed growth method and heat-treated at different temperatures.The influence of heat treatment on the morphology,size and optical properties of gold nanorods was analyzed by TEM,XRD,UV-vis and other methods.The results show that,as the heat treatment temperature of GNRs increases,the LSPR undergoes a blue shift,and the full-width at half maximum(FWHM)of the LSPR is significantly reduced.The reason for this phenomenon is obtained by investigating the change of LSPR of GNRs with average aspect ratios of 3.31,4.38,and 4.52 after holding at 110℃for different times;cetyltrimethylammonium bromide(CTAB)at the axial end of GNRs is more unstable than the side,making gold atoms more likely to fall off at high temperatures.This results in a significant reduction in length,which in turn results in a reduction of the aspect ratio and eventually causes LSPR blue shift and narrowing.