Sarath Kumar Chedharla Balaji, Reji Rence Painappallil, Sivalingam Yuvaraj, Kawazoe Yoshiyuki, Surya Velappa Jayaraman
Novel, Advanced, and Applied Materials (NAAM) Laboratory, Department of Physics and Nanotechnology, SRM Institute of Science and Technology Kattankulathur 603203 Tamil Nadu India
Laboratory of Sensors, Energy and Electronic Devices (Lab SEED), Department of Physics and Nanotechnology, SRM Institute of Science and Technology Kattankulathur 603203 Tamil Nadu India.
RSC Adv. 2024 Sep 4;14(38):28182-28200. doi: 10.1039/d4ra04843a. eCollection 2024 Aug 29.
Toxic metals present in drinking water pose a serious threat to the environment and human beings when present in abundance. In this work, we investigated the sensing ability of quantum dots (pristine CQDs, boron/nitrogen/sulphur (B/N/S)-doped CQDs, and BNQDs) of various sizes and morphologies (rectangular, circular, and triangular) towards toxic metals such as arsenic (As), cobalt (Co), nickel (Ni), copper (Cu), and lead (Pb) using quantum chemical density functional theory calculations in both gas and water phases. We probed the structural, electronic, and optical properties of the QDs. All the modelled QDs are energetically stable. Frontier molecular orbital analysis predicted that BNQDs are more chemically stable than all other CQDs. UV-vis absorption and Raman spectra analyses helped to understand the optical properties of all the QDs. Further, adsorption studies revealed that triangular pristine CQDs and sulphur-doped CQDs show higher adsorption affinity towards the toxic metals. The magnitude of adsorption energies follows the trend Ni > Pb > As > Cu > Co in most of the QDs. Several pristine and doped CQDs exhibited chemisorption towards the toxic metals, and hence, they can be used as adsorbents. However, a majority of BNQDs showed physisorption towards the metals, and therefore, they can be used as efficient optical sensors compared to CQDs. Further, the sensing ability of the QDs was explored through optical phenomena such as changes in UV-vis absorption spectra and fluorescence after metal adsorption. When compared to pristine CQDs and B/N/S-doped CQDs, metal complexation caused significant changes in the UV-vis absorbance peak intensities in BNQDs along with peak shifts. Moreover, metal interaction with the QDs increased their fluorescence lifetime with the highest values observed in Co-adsorbed triangular HC (152.30 ns), Pb-adsorbed rectangular HCS (21.29 ns), and As-adsorbed circular BNH (2.99 μs) among pristine CQDs, B/N/S-doped CQDs, and BNQDs, respectively. Overall, we believe that our first-of-its-kind computational prediction of the optical sensing ability of tailor-made zero-dimensional systems such as QDs will be a great aid for experimentalists in designing novel and rapid optical probes to detect toxic metals in drinking water.
饮用水中存在的有毒金属若大量存在，会对环境和人类构成严重威胁。在这项工作中，我们利用量子化学密度泛函理论计算，在气相和水相中研究了各种尺寸和形态（矩形、圆形和三角形）的量子点（原始碳量子点、硼/氮/硫（B/N/S）掺杂的碳量子点和硼氮量子点）对砷（As）、钴（Co）、镍（Ni）、铜（Cu）和铅（Pb）等有毒金属的传感能力。我们探究了量子点的结构、电子和光学性质。所有建模的量子点在能量上都是稳定的。前沿分子轨道分析预测，硼氮量子点比所有其他碳量子点在化学上更稳定。紫外可见吸收光谱和拉曼光谱分析有助于了解所有量子点的光学性质。此外，吸附研究表明，三角形原始碳量子点和硫掺杂的碳量子点对有毒金属表现出更高的吸附亲和力。在大多数量子点中，吸附能的大小遵循Ni > Pb > As > Cu > Co的趋势。几种原始的和掺杂的碳量子点对有毒金属表现出化学吸附，因此，它们可以用作吸附剂。然而，大多数硼氮量子点对金属表现出物理吸附，因此，与碳量子点相比，它们可以用作高效的光学传感器。此外，通过光学现象，如金属吸附后紫外可见吸收光谱和荧光的变化，探索了量子点的传感能力。与原始碳量子点和B/N/S掺杂的碳量子点相比，金属络合导致硼氮量子点的紫外可见吸收峰强度发生显著变化，并伴有峰位移。此外，金属与量子点的相互作用增加了它们的荧光寿命，在原始碳量子点、B/N/S掺杂的碳量子点和硼氮量子点中，分别在钴吸附的三角形HC（152.30 ns）、铅吸附的矩形HCS（21.29 ns）和砷吸附的圆形BNH（2.99 μs）中观察到最高值。总体而言，我们相信，我们对量子点等定制零维系统的光学传感能力的首创性计算预测，将极大地帮助实验人员设计新颖、快速的光学探针，以检测饮用水中的有毒金属。
