The use of photothermal techniques has become of special importance due to their versatile application in the thermal characterization of materials. Therefore, the thermal lens technique in the mismatched dual-beam mode is an alternative, sensitive and non-evasive tool that was used in this research to determine the thermal diffusivity of Moringa oleifera. The dual arrangement of the thermal lens technique is based on the use of an Ar+Xe excitation laser (422 nm) and a He–Ne laser (632 nm) test laser. Moringa solutions were prepared by green synthesis with different concentrations ranging from 1.56 mg·mL−1, 3.12 mg·mL−1, 6.25 mg·mL−1 to 12.50 mg·mL−1. Different optical techniques (UV–vis, FTIR, XPS and EDS) were used to characterize the Moringa leaf powders. Results showed that the increase of thermal diffusivity could be related to the presence of functional groups and metallic elements in Moringa elemental composition. In this work, it was found that the thermal diffusivity of Moringa increases with increasing concentration. This study will be useful for application in heat transport and drug release.

中文翻译：

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用热透镜作为敏感实验技术测定热扩散率与辣木浓度的相关性

由于光热技术在材料热表征中的广泛应用，光热技术的使用变得特别重要。因此，失配双光束模式下的热透镜技术是本研究中用于确定辣木的热扩散率的一种替代、灵敏且非回避的工具。热透镜技术的双重布置基于使用 Ar+Xe 激发激光器 (422 nm) 和 He-Ne 激光器 (632 nm) 测试激光器。辣木溶液通过绿色合成制备，浓度范围从1.56 mg·mL-1、3.12 mg·mL-1、6.25 mg·mL-1到12.50 mg·mL-1。使用不同的光学技术（UV-vis、FTIR、XPS 和 EDS）来表征辣木叶粉末。结果表明，热扩散率的增加可能与辣木元素组成中官能团和金属元素的存在有关。在这项工作中，发现辣木的热扩散率随着浓度的增加而增加。该研究将有助于在热传递和药物释放方面的应用。