Organic-free anatase TiO<inf>2</inf> paste for efficient plastic dye-sensitized solar cells and low temperature processed perovskite solar cells

Recently, the synthesis of fine TiO<inf>2</inf> paste with organic-free binder emerged as an indispensable technique for plastic photovoltaics due to the low temperature processing requirement. In this study, pure anatase TiO<inf>2</inf> nanoparticles and organic-free TiO<inf>2</inf>-sol were successfully synthesized individually in organic-free solution. By mixing the pure anatase TiO<inf>2</inf> with the newly developed TiO<inf>2</inf>-sol binder, mechanically robust and well-interconnected TiO<inf>2</inf> films were prepared via UV-irradiation at low temperature for applications in plastic dye-sensitized solar cells (p-DSSCs). The structural, electrical, and photovoltaic properties of the films as well as the devices were investigated by various techniques. The dye-loading amount of the obtained film is 2.6 times that of the P25 electrodes. As revealed by electrochemical impedance spectroscopy results, the film derived from the as-prepared anatase TiO<inf>2</inf> paste (A-TiO<inf>2</inf>) exhibits much smaller charge transport resistance and lower electron recombination rate than the P25 film, while the introduction of TiO<inf>2</inf>-sol into the paste can further remarkably decrease the resistance of the produced film (AS-TiO<inf>2</inf>). The p-DSSCs employing AS-TiO<inf>2</inf> photoanode yield a high efficiency up to 7.51%, which is 86% higher than the P25 reference cells and also 31% higher than the A-TiO<inf>2</inf> cell. As a proof of concept, the newly developed AS-TiO<inf>2</inf> paste was also applied to low temperature processed perovskite solar cells (PSCs), and a promising high efficiency up to 9.95% was achieved.Department of Applied Physic