Cellulose-inorganic hybrid structures as promising thermoelectric materials

Hybrid materials containing nanoscaled cellulosic constituents can be an attractive choice for thermoelectric energy harvesting, since it is possible to fabricate layered hybrid superlattice structures in a way that the thermal conductivity is reduced, while the electrical properties are simultaneously maintained. The aim of the presentation is to introduce approaches to construct such structures using various nanoscaled cellulosic materials such as cellulose nanocrystals (CNC), cellulose nanofibrils (CNF) and TEMPO-oxidized CNF with ZnO, and Earth-abundant inorganic component. Superlattice structures have been built on the solid substrates and on flexible CNF films using spincoating or dip coating along with the atomic layer deposition (ALD) method. Several characteristic features with respect to thermoelectric performance have been investigated which include for example resistivity, thermal conductivity and Seebeck coefficient of the hybrid materials. The results show that resistivity and thermal conductivity of the superlattice structures can be manipulated by the cellulosic thin layer nanoarchitecture.