Novel Charge Transport Materials for Improved Efficiency and Stability of Ultraflexible Organic Solar Cells

Organic photovoltaics, as one of the emerging PVs, has a unique feature of high flexibility by using flexible polymer substrates. By using a substrate and a passivation film with ultimate thinness, ultra-flexible energy harvesting devices can supply powers to wearable sensors on skin or textiles without causing discomfort to wearers [1,2]. The usage of such ultra-thin polymer film typically sacrifices gas barrier properties, and mechanical stresses with small bending radii cause new problems such as delamination at the interface. In this talk, we’ll discuss novel charge transport maaterials to achieve both high efficiency and reliability of ultrathin organic solar cells. The topics will include an organic-inorganic hybrid electron transport layers (ETL) enabling much improved mechanical robustness than a conventional oxide ETL [3], suppression of diffusion of ETL materials after a thermal aging process to enhance the stability of OPVs with non-fullerene active layers [4], and usage of liquid metals as solution-processed top cathodes enabling high-performance fully-solution processed organic photovoltaics [5]. In addition to the performance improvement of organic photovoltaic cells, we’ll show a lamination strategy of the ultra-thin organic photovoltaics to a complex curved surface [6].<br/>[1] S. Park et al., Nature 561, 516-521 (2018). [2] H. Jinno et al., Nat. Commun. 12, 2234 (2021). [3] F. Qin, Nat. Commun. 11, 4508 (2020). [4] S. Xiong, Adv. Sci. 9, 2105288 (2022). [5] J. Wang, ACS Appl. Mater. Interfaces, 14, 14165-14173 (2022). [6] R. Steven, Adv. Mater. 34, 2106683 (2022).