酸皮基磷光型碳点的制备及防伪应用

Preparation and anti-counterfeiting application of phosphorescent carbon dots based on pickled skin

摘要:

磷光材料凭借其优异的余辉特性、制备简便、低毒性等优点，在光学传感、生物成像、防伪等领域展现出良好的应用前景。制革加工中及皮革制品废弃后会产生大量浸酸山羊皮边角料，浸酸山羊皮已被证明可以用于制备荧光型碳点（CDs）并用于防伪；开发磷光型碳点有望丰富酸皮基碳点的种类并提升防伪效果。本研究以浸酸山羊皮为碳源，硼酸为硼源，采用热解法制备磷光型碳点（P-CDs）。探讨了浸酸山羊皮含量、反应pH、反应温度和反应时间等对P-CDs余辉时长的影响。结果表明当硼酸与浸酸山羊皮的质量比为3：0.12，反应pH为7，反应温度为225 ℃，反应时间为7.5 h时，碳点的余辉时间最长，达到12 s；该材料的发射波长为520 nm，对应明亮的绿色余辉。通过表征发现P-CDs平均粒径为4.42 nm左右，具有典型的石墨结构，硼原子成功的掺入碳点中形成了C-B、B-O等共轭链结构，稳定了三重激发态，延长了余辉时间。该材料在防伪及信息加密领域呈现潜在的应用价值。

Abstract:

Phosphorescent materials show good application prospects in optical sensing, biological imaging, anti-counterfeiting and other fields because of their excellent afterglow characteristics, simple preparation, low toxicity and other advantages. Large amounts of pickled skin (PS) offcut are produced easily during the leather making and abandon of leather products. It has been proved that PS can be used to prepare carbon dots (CDs) for anti-counterfeiting. The development of phosphorescent carbon dots (P-CDs) is expected to enrich the types of carbon dots with pickled skin and improve the anti-counterfeiting effect. In this paper, P-CDs were prepared by a one-step pyrolysis method using PS as carbon source and boric acid as boron source. The effects of PS content, reaction pH, reaction temperature and reaction time on the afterglow time of P-CDs were investigated. The results show that when the mass ratio of boric acid to PS is 3:0.12, the reaction pH is 7, the reaction temperature is 225 ℃, and the reaction time is 7.5 h, the afterglow time of P-CDs is the longest, reaching 12 s. The material has an emission wavelength of 520 nm, corresponding to a bright green afterglow. It is found that the average particle size of P-CDs is about 4.42 nm, which has a typical graphite structure. Boron atoms are successfully incorporated into the P-CDs to form C-B, B-O conjugate chain structure, which stabilizes the triple excited state and prolongs the afterglow time. It presents potential application value in the field of anti-counterfeiting and information encryption.