自组装单分子空穴传输层在反式钙钛矿太阳电池的研究进展

Research Progress of Self-assembled Hole-transporting Monolayers in Inverted Perovskite Solar Cells

空穴传输层在钙钛矿太阳电池(Perovskite solar cell, PSC)中起着抽取和传输钙钛矿层产生的光生空穴、抑制电子回流等重要作用,是构成高性能器件的重要组成部分.经典的空穴传输材料,如2,2',7,7'-四[N,N-二(4-甲氧基苯基)氨基]-9,9'-螺二芴(spiro-OMe TAD)、聚[双(4-苯基)(2,4,6-三甲基苯基)胺](PTAA)等,空穴迁移率低、价格昂贵等缺点限制了其规模化应用.近年来,在反式PSC中自组装单分子层(self-assembledmonolayers,SAM)作为空穴传输层广泛应用,提升了器件性能.SAM分子结构中含有锚定官能团,可以在衬底上形成单分子薄膜,有着材料消耗小、无需添加剂、寄生吸收低、能够兼容叠层器件和有利于大面积制造等优点,已成为PSC领域的研究热点.本综述结合PSC发展,按照SAM分子结构中锚定基团的不同,对近年来基于SAM的空穴传输层的研究进行了分类和归纳,结合分子骨架变化分析了结构变化对其特性及器件性能的影响.最后,对SAM作为空穴传输层的发展做了总结和展望.

Hole transport layer plays an important role in extracting and transporting photogenerated holes from the perovskite layer and suppressing back electron in Perovskite solar cell (PSC). It is an important component of high-performance devices. Classic hole transport materials, such as 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro- OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), etc., have high prices and low hole mobility, which limit the large-scale application. In recent years, self-assembled monolayers (SAM) have been widely used as hole transport layers in inverted PSC to improve device performance. SAM molecular structure contains anchoring functional groups, which can form a single molecule film on the substrate. It has the advantages of low material consumption, no need for additives, low parasitic absorption, compatibility with tandem devices, and is conducive to large-scale manufacturing. It has become a research hotspot in the field of perovskite solar cells. In the light of the development of PSC, this review classifies and summarizes the recent studies on SAM-based hole transport layers according to the different anchoring groups in the SAM molecular structure, and analyzes the effects of the molecular structure changes on the molecular properties and device performance. Finally, the development of SAM as a hole transport layer is summarized and prospected.