Krishnan S, Senthilkumar K
Department of Physics, Bharathiar University, Coimbatore 641 046, India.
J Phys Chem A. 2022 Aug 11;126(31):5079-5088. doi: 10.1021/acs.jpca.2c01631. Epub 2022 Aug 2.
Over a couple of decades perovskite solar cells have become a highly promising photovoltaic technology. Choosing a dopant-free Hole-Transporting Material (HTM) that offers protection to a perovskite layer from oxidation is one of the viable strategies while addressing the stability of perovskite solar cell. In this line of interest, tetrathiafulvale (TTF) derivatives have shown promise in the past. However, studies that focus on small-molecule TTF derivatives as potential HTM options are scarce. The present study is an attempt to explore the applicability of a few TTF derivatives as HTM in a perovskite solar cell. Here four TTF derivatives, namely, TTF-1 (experimentally reported in a previous study), TTF-2, DBTTF1, and TMTSF1, were studied through electronic structure calculations. The properties concerning HTM, such as impact of adsorption on molecular structure, absorption spectra, distribution of frontier molecular orbitals, interaction energy between TTF derivative and MAPbI surface, and charge transfer at an interface, were analyzed. Results show that TTF-2 has the expected energy-level alignment, transparency in the visible range of solar spectrum, and good charge-injection ability at the interface with a perovskite layer. Hence, TTF-2 could be a potential hole-transporting material for a perovskite solar cell, and it can perform better than TTF-1.
在过去的几十年里，钙钛矿太阳能电池已成为一种极具前景的光伏技术。选择一种能保护钙钛矿层免受氧化的无掺杂空穴传输材料（HTM）是解决钙钛矿太阳能电池稳定性问题的可行策略之一。在这方面，四硫富瓦烯（TTF）衍生物过去已显示出潜力。然而，专注于小分子TTF衍生物作为潜在HTM选项的研究很少。本研究旨在探索几种TTF衍生物作为HTM在钙钛矿太阳能电池中的适用性。这里通过电子结构计算研究了四种TTF衍生物，即TTF-1（先前的一项研究中有实验报道）、TTF-2、DBTTF1和TMTSF1。分析了与HTM相关的性质，如吸附对分子结构的影响、吸收光谱、前沿分子轨道的分布、TTF衍生物与MAPbI表面之间的相互作用能以及界面处的电荷转移。结果表明，TTF-2具有预期的能级排列、在太阳光谱可见光范围内的透明度以及在与钙钛矿层界面处良好的电荷注入能力。因此，TTF-2可能是一种用于钙钛矿太阳能电池的潜在空穴传输材料，并且它的性能可能优于TTF-1。
