Core/hybrid-shell structures boost thermoelectric performance of flexible inorganic/organic nanowire films

Interface control in inorganic/organic composites has always been regarded as one of the effective means to optimize their thermoelectric (TE) performance, and the past few years have witnessed its development, including carrier-energy filtering and phonon scattering. However, the energy barrier created by the band alignment at the composite interface depends on the Fermi level difference between the organic and inorganic components, which is difficult to be controlled by the common means. Herein, a core/hybrid-shell strategy aiming for efficient interface control is proposed to tune the energy barrier of the inorganic/organic core/shell nanowire interface. The Fermi level of hybrid-shell can be effectively controlled by separating the charge carriers compared to the single-shell composites. The energy barrier of the core/hybrid-shell interface is tuned to an appropriate position, and the energy filtering effect is utilized, resulting in a substantial improvement in power factor and reduction in thermal conductivity for the prepared core/hybrid-shell composites with good air-stability and flexibility. Moreover, both the flexible p type and p-n type TE devices based on the prepared core/hybrid-shell films yield excellent output properties with the maximum power densities of 41 and 45 μW·cm⁻² at a temperature difference of ca. 30 K, respectively. This study provides a novel strategy to improve the TE performance of the inorganic/organic composites, displaying great potential for low-power wearable electronics.