Preparation and Characterization of Spirobifluorene-based Hole-transporting Material for Highly Efficient and Stable Perovskite Solar Cells.
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초록
내용
Perovskite solar cells (PSCs) require both high efficiency and good long-term stability if they are to be commercialized. In order to prepare effective HTMs for PSCs, we synthesize a spirobifluorene-based HTM, DM, as a model system with a fine-tuned HOMO level in an effort to enhance the VOC value and realize a high Tg (~160oC) for thermally stable PSCs. The basic chemical and physical properties of the new HTM, DM, were thoroughly investigated by NMR, UV-Vis./PL spectroscopy, cyclic voltammetry and etc. Furthermore, a series of photovoltaic devices with different HTLs, spiro-OMeTAD and DM, have been fabricated and characterized. We could achieve a certified PCE of 22.6% (small-area cells, ~0.094 cm2) and 20.9% (large-area, ~1 cm2). The resultant device showed better thermal stability than the device with spiro-OMeTAD, maintaining almost 95% of its initial performance for more than 500h after thermal annealing at 60oC.