Santos Filipe M, Duarte Tiago A G, Correia Sandra F H, Pereira Rui F P, Conde Alexandra, Ribeiro Álvaro R, Braga Susana Santos, Ventura Sónia P M, Ferreira Rute A S, de Zea Bermudez Verónica, Nunes Sílvia C
Fiber Materials and Environmental Technologies (FibEnTech-UBI), Universidade da Beira Interior, R. Marquês de D'Ávila e Bolama, 6201-001 Covilhã, Portugal.
CQ-VR, Universidade de Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal.
ACS Nanosci Au. 2025 Feb 27;5(3):137-152. doi: 10.1021/acsnanoscienceau.4c00048. eCollection 2025 Jun 18.
In this work, a singular system capable of interacting with the entire visible region of the solar spectrum is produced by combining carbon dots (CDs) and chlorophyll (Chl) pigments, entirely derived from the microalga Chlorella pyrenoidosa. The process involves the digestion of the C. pyrenoidosa cellular wall in an acetic acid:cholinium chloride (AA/ChCl) solvent, followed by a microwave reaction. The resulting CDs exhibit excitation and emission maxima at 461 and 528 nm, respectively. The Chl centers enable a secondary photoluminescence (PL) process, thus ensuring that the as-prepared CDs/Chl system (CDCS) can also interact with the farther red region of the visible spectrum. The luminescence properties of CDCS are concentration-dependent, undergoing a blue shift with dilution. Confocal microscopy provided insights into the protection of Chl pigments throughout the process. Furthermore, the consequences arising from the addition of poly-(ethylene glycol) oligomers (PEG-200) are also analyzed. The results demonstrate that the interaction between CDCS and PEG-200 significantly modifies the PL intensity and emission wavelengths, especially at higher PEG-200 concentrations. This suggests that PEG-200 can act as a modulating agent, stabilizing and even preventing the CDs' fluorescence quenching while also affecting the PL properties of Chl. This work presents interesting possibilities for the development of multifunctional luminescent systems derived from microalgae biomass by addressing how these microorganisms can function not only as precursors in the formation of advanced functional materials but also as an integrated component of these systems. As an added benefit, a luminescent solar concentrator (LSC) was fabricated, revealing photostability, as well as optical and power conversion efficiency values of 11 and 0.2%, respectively, values comparable to state-of-the-art CD-based LSCs.
在这项工作中，通过将完全源自微藻小球藻的碳点（CDs）和叶绿素（Chl）色素相结合，制备出了一种能够与太阳光谱的整个可见光区域相互作用的奇异体系。该过程包括在醋酸：氯化胆碱（AA/ChCl）溶剂中消化小球藻的细胞壁，然后进行微波反应。所得的碳点分别在461和528nm处表现出激发和发射最大值。叶绿素中心实现了二次光致发光（PL）过程，从而确保所制备的碳点/叶绿素体系（CDCS）也能与可见光谱中更远的红色区域相互作用。CDCS的发光特性取决于浓度，稀释时会发生蓝移。共聚焦显微镜为整个过程中叶绿素色素的保护提供了深入了解。此外，还分析了添加聚（乙二醇）低聚物（PEG - 200）所产生的影响。结果表明，CDCS与PEG - 200之间的相互作用显著改变了PL强度和发射波长，尤其是在较高的PEG - 200浓度下。这表明PEG - 200可以作为一种调节剂，稳定甚至防止碳点的荧光猝灭，同时也影响叶绿素的PL特性。这项工作通过探讨这些微生物如何不仅作为先进功能材料形成的前体，而且作为这些体系的一个集成组件，为开发源自微藻生物质的多功能发光体系提供了有趣的可能性。另外，制造了一种发光太阳能聚光器（LSC），其显示出光稳定性，以及光学和功率转换效率值分别为11%和0.2%，这些值与基于碳点的先进LSC相当。
