Das Adhikari Ramkrishna, Baishya Himangshu, Patel Mayur Jagdishbhai, Yadav Deepak, Iyer Parameswar Krishnan
Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
Small. 2024 Nov;20(46):e2404588. doi: 10.1002/smll.202404588. Epub 2024 Aug 10.
The quality of the buried heterojunction of nickel oxide (NiO)/perovskite is crucial for efficient charge carrier extraction and minimizing interfacial non-radiative recombination in inverted perovskite solar cells (PSCs). However, NiO has limitations as a hole transport layer (HTL) due to energy level mismatch, low conduction, and undesirable redox reactions with the perovskite layer, which impede power conversion efficiency (PCE) and long-term stability. In this study, para-amino 2,3,5,6-tetrafluorobenzoic acid (PATFBA) is proposed as a bifacial defect passivator to tailor the NiO/perovskite interface. The acid group and adjacent fluorine atoms of PATFBA effectively passivate NiO surface defects, thereby improving its Ni/Ni ratio, hole extraction capability, and energy band alignment with perovskite, while also providing active sites for homogenous nucleation. Meanwhile, the amine and adjacent fluorine atomsstabilize the buried perovskite interface by passivating interfacial defects, resulting in higher crystalline perovskite films with supressed non-radaitive recombination. Furthermore, the PATFBA buffer layer prevents redox reactions between Ni and perovskite.These synergistic bi-directional interactions lead to optimized inverted PSCs with a PCE of 20.51% compared to 16.89% for pristine devices and the unencapsulated PATFBA-modified devices exhibit outstanding thermal and long-term stability. This work provides a new engineering approach to buried interfaces through the synergy of functional groups.
氧化镍（NiO）/钙钛矿掩埋异质结的质量对于高效电荷载流子提取以及最小化倒置钙钛矿太阳能电池（PSC）中的界面非辐射复合至关重要。然而，由于能级不匹配、低电导率以及与钙钛矿层发生不良氧化还原反应，NiO作为空穴传输层（HTL）存在局限性，这阻碍了功率转换效率（PCE）和长期稳定性。在本研究中，提出对氨基2,3,5,6 - 四氟苯甲酸（PATFBA）作为一种双功能缺陷钝化剂来优化NiO/钙钛矿界面。PATFBA的酸基团和相邻氟原子有效地钝化了NiO表面缺陷，从而提高了其Ni/Ni比、空穴提取能力以及与钙钛矿的能带对齐，同时还为均匀成核提供了活性位点。与此同时，胺基和相邻氟原子通过钝化界面缺陷稳定了掩埋的钙钛矿界面，从而得到具有更低非辐射复合的更高结晶度钙钛矿薄膜。此外，PATFBA缓冲层可防止Ni与钙钛矿之间的氧化还原反应。这些协同的双向相互作用导致优化后的倒置PSC的PCE达到20.51%，而原始器件的PCE为16.89%，并且未封装的PATFBA修饰器件表现出出色的热稳定性和长期稳定性。这项工作通过官能团的协同作用为掩埋界面提供了一种新的工程方法。
