原子掺杂对不同配体中碳点光致发光性能的影响研究

Study on Photoluminescence Characteristics of Carbon Dots in Different Ligands

摘要:

碳点具有光学性质可调及光稳定性好的特性，被广泛应用于各种工业领域，特别是光致发光领域。碳点的光致发光与碳源的分子结构密切相关，其中碳点自身分散性会影响发光强度。为研究碳点在不同配体中的光致发光性能，采用掺杂合成-溶液透析法，制备了3种分子结构的碳点材料，掺杂碳点NCDs、共掺杂碳点NSCDs及混合碳点NCDs+NSCDs。利用扫描电子显微镜、透射电子显微镜和X射线衍射表征了其显微形貌，利用紫外可见光谱仪测试了其吸光强度，配置了乙醇、有机溶液进行紫外和自然光照射发光测试，研究了3种碳点的分散性及发光性能。研究结果表明，NCDs呈二维细片状形貌，NSCDs的掺杂原子负载在其表面，而NCDs+NSCDs的掺杂原子团具有强的单分散性。3种碳点均为均匀分布的纳米颗粒，尺寸大小约1.8 nm。以NCDs的碳特征峰为初始位置基准，NSCDs的特征峰明显向左发生了偏移，NCDs+NSCDs的特征峰也发生了向左偏移，但显著程度低于 NSCDs。其主要原因是掺杂原子团的引入使晶面间距发生变化，影响了碳点晶面间距的大小，表明掺杂原子已引入碳点中。3种碳点在自然光照射下均发出绿色荧光，且随着激发波长越长偏向蓝移，其中NCDs+NSCDs荧光发光颜色最深，表明其具有更强的亲水性和分散性。分散性的增强会使碳点的发光强度增强，NCDs+NSCDs在不同配体中的发光强度最强，表明其分散性强，增强了其光致发光性能。本研究为碳点发光性能在光致发光及其他领域的应用提供了参考。

Abstract:

Carbon dots are widely used in various fields especially in the field of photoluminescence due to their adjustable optical properties and good optical stability. The photoluminescence of carbon dots is closely related to the molecular structure of carbon sources，in which the dispersion of carbon dots affects their luminescence intensity. In order to study the photoluminescence properties of carbon dots in different ligands，carbon dots NCDs，NSCDs and NCDs+NSCDs were prepared by doping synthesis and solution dialysis ，the morphologies of the three carbon dots were observed by scanning electron microscopy，transmission electron microscopy， and X-ray diffraction. The light absorption intensity of the three carbon dots was measured by UV-vis. The dispersion and luminescence properties of the three carbon points were also studied. The results show that the morphology of carbon dots NCDs is two-dimensional fine sheet，the heteroatoms of carbon dots NSCDs are loaded on its surface ，and the doped atomic groups of carbon dots NCDs+NSCDs have strong monodispersion. The three carbon dots are uniformly distributed as nanoparticles with a size of about 1.8 nm. Taking the carbon characteristic peak of NCDs as the initial position reference，the characteristic peak of NSCDs has obviously shifted to the left ，and the characteristic peak of NCDs+NSCDs also shifted to the left，but it is not as obvious as NSCDs. This is because the introduction of doping atomic groups changes the crystal face spacing，thus affecting the size of the crystal face spacing of carbon dots，which shows that doping atoms have been introduced into the carbon dots. The three carbon dots all emit green fluorescence under natural light ，and tend to shift to blue with the longer excitation wavelength ，among which the mixed carbon dots have the deepest fluorescence color ，indicating that the carbon dots of NCDs+NSCDs have stronger hydrophilicity and dispersion，and the enhancement of dispersion will enhance the luminous intensity of carbon dots. The emission intensity of NCDs+NSCDs carbon dots in different ligands is the strongest， indicating that its dispersion is enhanced ，thus enhancing its photoluminescence performance. As a new generation of carbon materials，carbon dots have promoted the development of various fields and further understanding of carbon materials.