n-doped inorganic molecular clusters as a new type of hole transport material for efficient organic solar cells

At present, PEDOT:PSS and MoO3 are the most widely used hole transport layer (HTL) in organic solar cells (OSCs); however, some drawbacks still limit their practical use. In this study, we developed a facile method to enhance the conductivity of a polyoxometalate-based inorganic cluster (PIC) without sacrificing its high work function nature. An inorganic cluster HPMO:Sn with excellent hole collection ability was prepared and used as an HTL in an OSC achieving a power conversion efficiency (PCE) of 17.3%. To the best of our knowledge, the photovoltaic performances are among the best devices reported in the field. Moreover, HPMO:Sn possesses the merits of a definite and stable chemical structure and is low cost, and HPMO:Sn can be easily prepared without any post-treatment. Besides, we prove that the HPMO:Sn HTL is very compatible with blade coating, i.e., an OSC of 1.0 cm(2) was fabricated using a blade-coated HPMO: Sn film to attain an efficiency of 15.1%.

Automated summary

A new inorganic cluster HPMO:Sn has been developed as a hole transport layer (HTL) in organic solar cells, showing excellent photovoltaic performance with low cost and stable chemical structure. It is also compatible with blade coating process, demonstrating high efficiency in device fabrication.