In this study, dilution analysis and anion exchange chromatography (AEC) were employed to provide insights into the photoluminescence (PL) of carbon nanodots (CNDs). A stepwise dilution process revealed that some of the fluorophores with higher energy emission were quenched in the high concentration solution and appeared in the dilute solutions. AEC fractionation led to seven sorts of CND fractions with similar surface charges. The fractionation for this CND mixture showed that excitation wavelength dependence was lower for separated CND particles. The wavelength dependence of excitation spectra could be due to energy exchange between particles that was reduced in diluted solutions and separated fractions. Multivariate analysis of AEC's data demonstrated that there were five distinct fluorophores, which formed the total CND emission. It is interesting that none of these fluorophores had a clear contribution to the surface charge of the CND particles. Further characterization through FTIR spectroscopy and 1 H NMR revealed that optical properties of CNDs did not follow the surface functional groups in CNDs. This situation means that the optical behaviour of particles and their fluorophores differed depending on the surface functional groups.

中文翻译：

---

用于理解碳纳米点中的光致发光和能量转移的多路数据分析方法。

在这项研究中，采用稀释分析和阴离子交换色谱（AEC）来深入了解碳纳米点（CND）的光致发光（PL）。逐步稀释过程表明，一些具有较高能量发射的荧光团在高浓度溶液中被淬灭并出现在稀溶液中。AEC分馏产生了7种具有相似表面电荷的CND馏分。此CND混合物的分馏结果表明，分离的CND颗粒的激发波长依赖性较低。激发光谱的波长依赖性可能是由于颗粒之间的能量交换，该能量交换在稀释溶液和分离的馏分中减少了。AEC数据的多变量分析表明，有五个不同的荧光团构成了CND的总发射量。有趣的是，这些荧光团均未对CND颗粒的表面电荷有明显贡献。通过FTIR光谱和1 H NMR进一步表征表明，CND的光学性质不遵循CND中的表面官能团。这种情况意味着颗粒及其荧光团的光学行为取决于表面官能团而有所不同。