One step facile synthesis of a novel anthanthrone dye-based, dopant-free hole transporting material for efficient and stable perovskite solar cells

Perovskite solar cell (PSCs) technology has made a tremendous impact in the solar cell community due to the exceptional performance of PSCs as the power conversion efficiency (PCE) surged to a world record of 22% within the last few years. Despite this high efficiency value, the commercialization of PSCs for large area applications at affordable prices is still pending due to the low stability of the devices under ambient atmospheric conditions and the very high cost of the hole transporting materials (HTMs) used as the charge transporting layer in these devices. To cope with these challenges, the use of cheap HTMs can play a dual role in terms of lowering the overall cost of perovskite technology as well as protecting the perovskite layer to achieve a higher stability. To achieve these goals, various new organic hole transporting materials (HTMs) have been proposed. In this study, we used a unique and novel anthanthrone (ANT) dye as a conjugated core building block and an affordable moiety to synthesize a new HTM. The commercially available dye was functionalized with an extended diphenylamine (DPA) end capping group. The newly developed HTM, named DPA-ANT-DPA, was synthesized in a single step and used successfully in mesoporous perovskite solar cell devices, achieving a PCE of 11.5% under 1 Sun condition with impressive stability. The obtained device efficiency is amongst the highest as compared to that of other D-A-D molecular design and low band gap devices. This kind of low cost HTM based on an inexpensive starting precursor, anthanthrone dye, paves the way for the economical and large-scale production of stable perovskite solar cells.