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利用淀积在玻璃衬底上的金银合金薄膜作为表面等离子体共振(SPR)芯片,构建了Kretschmann结构的近红外波长检测型SPR传感器.采用不同浓度的葡萄糖水溶液测试了金银合金薄膜SPR传感器的折射率灵敏度.实验结果表明随着入射角从7.5°增大到9.5°,SPR吸收峰的半高峰宽从292.8nm减小到131.4nm,共振波长从1215nm蓝移到767.7nm,折射率灵敏度从35648.3nm/RIU减小到9363.6nm/RIU.在相同的初始共振波长(λR)下获得的金银合金薄膜SPR折射率灵敏度高于纯金膜(纯金膜在λR=1215nm下的折射率灵敏度为29793.9nm/RIU).利用1μmol/L的牛血清蛋白(BSA)水溶液测试了传感器对蛋白质吸附的响应.结果表明,BSA分子吸附使得金银合金薄膜SPR吸收峰红移了12.1nm而纯金膜SPR吸收峰仅红移了9.5nm.实验结果还表明,在相同λR下,金银合金薄膜SPR吸收峰的半高峰宽大于纯金膜的半高峰宽,因此其光谱分辨率比纯金膜SPR传感器低.
A Kretschmann structure-based near-infrared wavelength detection type SPR sensor was fabricated by using a thin film of gold-silver alloy deposited on a glass substrate as a surface plasmon resonance (SPR) chip.The gold-silver alloy thin film SPR sensor was tested with different concentrations of aqueous dextrose solution The experimental results show that the half-height peak width of SPR absorption decreases from 292.8nm to 131.4nm and the resonance wavelength shifts from 1215nm to 767.7nm as the incident angle increases from 7.5 ° to 9.5 °. The refractive index sensitivity From 35648.3nm / RIU to 9363.6nm / RIU.The SPR refractive index sensitivity of gold-silver alloy films obtained at the same initial resonance wavelength (λR) is higher than that of pure gold films (refractive index of pure gold film at λR = 1215nm The sensitivity was 29793.9nm / RIU) .The response of the sensor to protein adsorption was tested using 1μmol / L BSA aqueous solution.The results showed that the absorption of BSA molecule caused the red shift of SPR absorption band of gold-silver alloy film by 12.1nm The SPR absorption peak of the gold film is only red shifted by 9.5 nm.The experimental results also show that at the same λR, the half-height width of the SPR absorption peak of the gold-silver alloy film is larger than that of the pure gold film, Membrane SPR transmission Low devices.