Hasan A M Mahmudul, Susan Md Abu Bin Hasan
Department of Chemistry, University of Dhaka Dhaka-1000 Bangladesh
Dhaka University Nanotechnology Center (DUNC), University of Dhaka Dhaka-1000 Bangladesh.
RSC Adv. 2024 Mar 4;14(11):7616-7630. doi: 10.1039/d4ra00601a. eCollection 2024 Feb 29.
Dye-sensitized solar cells (DSSCs) play a crucial role in the realm of renewable energy technology by converting solar energy into electrical energy in an efficient and cost-effective way. In the pursuit of improving the photoconversion efficiency (PCE) of DSSCs, this work aims at fabricating a new counter electrode (CE) using a binary composite of heteroatom-doped carbon dots (C-dots) and functionalized multi-walled carbon nanotubes (o-MWCNTs). We demonstrate that this binary composite exhibits superior performance to pristine o-MWCNTs, resulting in a remarkable enhancement in the PCE. The PCE of the o-MWCNT/C-dots composite was measured at an impressive 4.28%, significantly outperforming the pristine o-MWCNT electrode, which yielded an efficiency of 2.24%. The enhanced performance of the o-MWCNT/C-dots composite can be attributed to the synergistic effects of heteroatom-doped C-dots since their binding to the o-MWCNTs by activated oxygenic surface functional groups increases the surface area from 218 to 253 m g. This enhanced surface area results from the reduction of π-π stacking interactions of the individual tubes and production of a new hollow channel in the structure that provides an ideal scaffold for I adsorption and electron transfer. We demonstrate the role of C-dots on MWCNT's property modulation toward higher PCE by density functional theory (DFT) calculation and electrochemical analysis. Electron-excess N and S doped C-dots exhibit strong catalytic activity, allowing for rapid electron transfer processes in the CE-electrolyte surface the donor acceptor mechanism, whereas electron-deficient B doped C-dots undermine the cell performance by forming a charge recombination trap at the CE surface. The synthesized composite has higher redox reversibility up to 100 CV cycles and chemical stability, studied by the post-performance material characterization. The findings offer a promising avenue for the development of high-performance DSSCs, which will help to promote sustainable and renewable energy technologies.
染料敏化太阳能电池（DSSCs）通过以高效且经济高效的方式将太阳能转化为电能，在可再生能源技术领域发挥着至关重要的作用。在追求提高DSSCs的光电转换效率（PCE）的过程中，这项工作旨在使用杂原子掺杂碳点（C-点）和功能化多壁碳纳米管（o-MWCNTs）的二元复合材料制备一种新型对电极（CE）。我们证明，这种二元复合材料表现出优于原始o-MWCNTs的性能，从而使PCE显著提高。o-MWCNT/C-点复合材料的PCE测得令人印象深刻的4.28%，明显优于原始o-MWCNT电极，其效率为2.24%。o-MWCNT/C-点复合材料性能的提高可归因于杂原子掺杂C-点的协同效应，因为它们通过活性含氧表面官能团与o-MWCNTs结合，使表面积从218增加到253 m²/g。这种增加的表面积是由于单个管子的π-π堆积相互作用减少以及结构中产生了一个新的中空通道，该通道为I吸附和电子转移提供了理想的支架。我们通过密度泛函理论（DFT）计算和电化学分析证明了C-点在MWCNT性能调制以实现更高PCE方面的作用。电子过剩的N和S掺杂C-点表现出很强的催化活性，允许在CE-电解质表面通过供体-受体机制进行快速电子转移过程，而电子不足的B掺杂C-点通过在CE表面形成电荷复合陷阱破坏电池性能。通过性能后材料表征研究，合成的复合材料具有高达100个循环伏安（CV）循环的更高氧化还原可逆性和化学稳定性。这些发现为高性能DSSCs的开发提供了一条有前途的途径，这将有助于推动可持续和可再生能源技术的发展。
