Acta Chimica Sinica ›› 2019, Vol. 77 ›› Issue (8): 741-750.DOI: 10.6023/A19060200 Previous Articles     Next Articles



王梦涵a, 万里b, 高旭宇a, 袁文博a, 方俊峰b, 陶友田a, 黄维a,c   

  1. a 江苏省柔性电子重点实验室 南京工业大学先进材料研究院 南京 211816;
    b 中国科学院宁波材料技术与工程研究所 宁波 315201;
    c 西北工业大学柔性电子研究院 西安 710072
  • 投稿日期:2019-06-06 发布日期:2019-06-28
  • 通讯作者: 方俊峰, 陶友田;
  • 基金资助:


Synthesis of D-π-A-π-D Type Dopant-Free Hole Transporting Materials and Application in Inverted Perovskite Solar Cells

Wang Menghana, Wan Lib, Gao Xuyua, Yuan Wenboa, Fang Junfengb, Tao Youtiana, Huang Weia,c   

  1. a Key Lab for Flexible Electronics, Institute of Advanced Materials, Nanjing Tech University, Nanjing 211816;
    b Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201;
    c Shaanxi Institute of Flexible Electronics, Northwestern Polytechnical University, Xi'an 710072
  • Received:2019-06-06 Published:2019-06-28
  • Contact: 10.6023/A19060200;
  • Supported by:

    Project supported by the National Key Research and Development Program of China for the Joint Research Program between China and European Union (No. 2016YFE0112000), National Natural Science Foundation of China (No. 61761136013), and the Natural Science Foundation of Jiangsu Province (No. BK20160042).

Perovskite solar cells (PVSCs) have recently gained much attention for the advantages of low cost and high efficiency. Based on the different device structures, PVSCs can be simply classified into conventional and inverted categories. Compared with the inverted devices, conventional PVSCs generally exhibited higher PCE. Especially, a milestone PCE value of 24.3% was obtained in conventional PVSCs. However, the complexity and high-temperature process in device fabrication further limit their application in flexible and large-scale devices, while the inverted PVSCs can make up the shortcomings of the conventional PVSCs. Commonly, PVSCs devices contain electrodes, electron/hole transporting layers and the perovskite layer. Among the function layers, hole transporting layers (HTLs) play a crucial role in improving the photovoltaic performance of inverted PVSCs. From the materials point of view, the efficient hole transporting materials (HTMs) are mostly inorganic compounds and polymers. On the other side, taking advantages of easy modification, low price, easy preparation and homogeneity in batches, small molecular HTMs afford superior promising in fabricating efficient and stable PVSCs. However, up to date, small molecular HTMs are relatively less explored. To enrich the material species of small molecular HTMs and illustrate their superiorities in constructing stable PVSCs, in this paper, we designed and synthesized three D-π-A-π-D type small molecular HTMs based on triphenylamine (TPA) unit, namely 1-T, 1-OT and 1-OTCN. The optoelectronic properties of these molecules were modified by introducing different electron acceptor/donor groups. Afterwards, employing as dopant-free HTMs in inverted PVSCs, the three small molecules demonstrated distinguished performance. We found that introduction of electron-donating methoxy into 1-T, 1-OT exhibited increased energy levels and hole mobility. On the other hand, the energy levels of 1-OTCN were down-shifted compared to 1-OT, which was attributed from the stronger electron-withdrawing ability of dicyanovinylene group than carbonyl group. Among the devices with new HTMs, 1-OTCN based PVSCs achieved the best PCE of 16.8%, with open-circuit voltage (VOC) of 1.09 V, short-circuit current density (JSC) of 20.13 mA·cm-2 and fill factor (FF) of 78%. Compared with other HTMs, the higher JSC of 1-OTCN based PVSCs was ascribed from more efficient charge transfer and extraction in the interface of HTL/perovskite. Moreover, in contrast with the hydrophilicity of PEDOT:PSS, the hydrophobicity of 1-OTCN contributed to the satisfactory stability of PVSCs.

Key words: perovskite solar cells, organic small molecular hole transporting materials, triphenylamine, D-π-A-π-D, dopant-free, stability