Kevin Musselman1
University of Waterloo1
A femtosecond-laser technique is presented for the fabrication of 2D nanoparticles. Flakes of 2D materials are dispersed in different solvents and irradiated with a femtosecond laser for different durations at different powers. The laser irradiation results in breaking of the flakes into smaller nanoparticles. Simultaneously, laser-dissociated solvent atoms can bond with the nanoparticles to form functionalized 2D nanoparticles, where the choice of solvent determines the nature of the functionalization [1]. Functionalization of different 2D nanoparticles, including graphene, graphene oxide, molybdenum disulfide, tungsten disulfide, and boron nitride, with carbon, oxygen, nitrogen, and halogens is demonstrated. Under some conditions, conversion of the starting 2D material is possible. For example, the transformation of MoS<sub>2</sub> powder to sub-stoichiometric MoO<sub>3-x</sub> nanosheets is demonstrated [2]. The functionalized 2D nanoparticles can be tailored for various applications including gas sensing [3], photothermal cancer therapy [2], fluorescence chemical sensing, and photovoltaics [4]. The incorporation of halogenated graphene particles into perovskite solar cells will be discussed in detail. The graphene particles are found to improve the humidity resistance of the perovskite solar cells and simultaneously enhance hole extraction.<br/><br/>[1] K. Ibrahim et al. Small 15:1904415 (2019).<br/>[2] F. Ye et al. Chem. Mater. 33:4510 (2021).<br/>[3] K. Mistry et al. Adv. Mat. Tech. 5:2000704 (2020). <br/>[4] K. Ibrahim et al. Solar Energy 224:787 (2021).