高效紫色荧光碳点制备及光学pH检测应用

Preparation and Application of Highly Fluorescent Purple-emissive Carbon Dots for Optical pH Measurement

紫色荧光碳点(P-CDs)的制备通常存在制备复杂、量子产率低、荧光强度低等缺点。本文以邻苯二胺(OPD)和间苯二胺(MPD)为氮源,柠檬酸为碳源,在120℃的低温条件下,通过一步水热法成功获得了绝对量子产率为5.3%的高荧光P-CDs。XPS和FT-IR结果表明,所有合成的P-CDs具有相似的官能团,但含量不同;OPD/MPD的比例可有效调控P-CDs的荧光强度。所得P-CDs具有较好的光稳定性和盐稳定性。值得注意的是,当pH为1~3或10~13时,P-CDs的荧光颜色明显转变为绿色。上述独特的pH依赖性荧光色行为确保了其在光学pH传感中的潜在应用。

The preparation of purple-emissive carbon dots(P-CDs)usually accompanies the disadvantages of com-plicated preparation,low quantum yield(QY)and low fluorescence intensity.Herein,we used o-phenylenediamine(OPD)and m-phenylenediamine(MPD)as nitrogen sources and citric acid(CA)as carbon source to prepare P-CDs.Only using simple one-step hydrothermal method under a low experimental temperature of 120℃,we success-fully obtained highly luminescent P-CDs with absolute QY of 5.3%.The results of XPS and FT-IR revealed that all synthesized P-CDs contained similar functional groups but with different contents.The fluorescence intensity of P-CDs could be effectively regulated by the amount ratio of OPD to MPD.The resulting P-CDs also possessed consider-able photostability and salt stability.Notably,the fluorescence color of P-CDs remarkably transformed into green as the pH being in the range of 1-3 or 10-13.The aforementioned unique pH-dependent fluorescence chromic behav-iors ensured the potential application in the optical pH sensing.