Vallejo, Javier P.Javier P.VallejoMercatelli, LucaLucaMercatelliMartina, Maria RaffaellaMaria RaffaellaMartinaDi Rosa, DanieleDanieleDi RosaDELL'ORO, AldoAldoDELL'OROLugo, LuisLuisLugoSani, ElisaElisaSani2021-01-252021-01-2520190960-1481http://hdl.handle.net/20.500.12386/29956The optical properties of nanofluids are peculiar and interesting for a variety of applications. Among them, the high light extinction coefficient of nanofluids can be useful in linear parabolic concentrating solar systems, while their properties under high light irradiation intensities can be exploited for direct solar steam generation. The optical characterization of colloids, including the study of non-linear optical properties, is thus a needed step to design the use of such novel materials for solar energy exploitation. In this work, we analysed two different types of nanofluids, consisting of polycarboxylate chemically modified graphene nanoplatelets (P-GnP) and sulfonic acid-functionalized graphene nanoplatelets (S-GnP) dispersed in water, at three concentrations from 0.005 wt% to 0.05 wt%. Moderately stable nanofluids were achieved with favourable light extinction properties, as well as a non-linear optical behaviour under high input solar intensities.STAMPAenArticle10.1016/j.renene.2019.04.0752-s2.0-85064737267000472241100069https://www.sciencedirect.com/science/article/abs/pii/S0960148119305592FIS/01 - FISICA SPERIMENTALEERC sectors::Physical Sciences and Engineering::PE2 Fundamental constituents of matter: particle, nuclear, plasma, atomic, molecular, gas, and optical plasma::PE2_9 Optics, non-linear optics and nano-optics