Strongly reduced thermal conductivity in hybrid ZnO/nanocellulose thin films

Utilizing a combination of atomic layer deposition and dip-coating techniques, we have incorporated natural nanocellulose fibers into an inorganic matrix in order to create a layered hybrid inorganic–organic thin-film structure. Such layer-engineered hybrid materials with an unorthodox combination of components are highly potential candidates for exciting new properties. Here, we show a more than an order of magnitude reduction in the cross-plane thermal conductivity for ZnO thin films achieved with the regular inclusion of the cellulose nanofiber layers. We foresee that a similar approach as presented here for ZnO could also be applied to other inorganic materials based on earth-abundant elements to influence their thermal transport properties.