DNA手性分子/二维TMDCs材料的自旋-能谷极化性能及应用机理研究

This project aims to study the spin-valley polarization and application mechanism of DNA chiral molecules/two-dimensional transition metal chalcogenides (TMDCs) materials, so as to design and construct a convenient new DNA biosensor which can be used for biological contamination detection only by optical test..Recent studies have shown that double-stranded DNA molecules act as chiral molecules with circular dichroism. On the other hand, two-dimensional TMDCs materials have spin-valley circularly polarized dichroic selectivity due to their unique strong spin-orbit coupling or interlayer coupling. Based on this theory, two-dimensional TMDCS materials with spin-valley polarization properties are synthesized, and use them as a matrix to absorb single-stranded probe DNA molecule. The hybrid DNA will be selected on the principle of base pairing of DNA molecules. When the linearly polarized light across the DNA chiral molecule, it is converted into circularly polarized light, and excited the valley of the two-dimensional TMDCs material, which can be characterized by photoluminescence and then can be used as a DNA biosensor. This project will expand the research direction of the spin-valley polarization of two-dimensional TMDCs, and also provide a new idea for the analysis and detection of biological pollution.

本项目旨在对DNA手性分子/二维过渡金属硫属化物（TMDCs）材料的自旋-能谷极化性能及应用机理进行研究，从而设计并构建一种便捷的仅采用光学测试便可实现生物污染检测的新型DNA生物传感器。.研究表明双链DNA分子作为手性分子，具有圆二色性；二维TMDCs材料由于强的自旋-轨道耦合或层间耦合作用而具有自旋-能谷圆偏振光二色性选择吸收性。本项目以此为理论基础，合成具有自旋-能谷极化性能的二维TMDCS材料，并以该材料为基体吸附单链探针DNA分子，结合DNA分子碱基配对原则选择杂交DNA分子以实现DNA生物传感器的构建。当线偏振光经过杂交成双链的DNA手性分子时转化为圆偏振光，激发二维TMDCs材料的能谷，可以通过荧光光谱仪进行表征，从而实现DNA生物传感器的应用。本项目的研究不仅拓展了二维TMDCs材料自旋-能谷极化效应的研究方向，也为生物污染的分析与检测提供新的思路。

在本项目中，探究了具有生物特异性的光学活性分子DNA对二维TMDCs材料能谷极化的影响。按照项目计划和研究方案，取得了以下几方面的进展。（1）采用熔盐法和双功能钠盐法制备了多种二维TMDCs材料，并通过对化学气相沉积过程中源材料，气流以及压力等各种因素调控，制备出了包括MoS2，WS2以及WSe2在内的高质量单层膜，并对其宏观物理性能进行了表征。（2）为了更好的实现二维TMDCs材料的能谷极化，我们构建了两种异质结构，BN/MoS2以及WSe2/SrTiO3，为TMDCs材料能谷极化的有效调控奠定了基础。（3）我们选取了三种手性分子及多种DNA序列，通过物理吸附，实现对TMDCs及其异质结构的负载修饰。通过手性结构的修饰，TMDCs材料在室温下表现出明显的极化特性。特别的，当WSe2/STO异质结构负载DNA分子时，有且仅有完全匹配的DNA双链分子表现出最大范围的能谷极化，为TMDCs的自旋能谷极化性能应用于生物污染检测奠定了理论基础。

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