Decoupling of thermoelectric parameters in two-dimensional hyperbranched platinum acetylides

Abstract

Hyperbranched architectures with two-dimensional π-extension are innovatively introduced to construct advanced organic thermoelectrics, affording a promising method to decoupling the tradeoff relation of electrical conductivity and Seebeck coefficient. Theoretical calculations disclose that the incorporation of heavy atom platinum on the branched chain is significant for sharping their density of states nearby the Fermi levels via d(π)-p(π) interactions, while the strong orbital overlaps of p(π)-p(π) interactions along the main chain direction ensures an efficient π-delocalization. Ultraviolet photoelectron spectroscopy and scanning electron microscopy measurements demonstrate an obviously improved doping efficiency and morphologic stability of the hyperbranched platinum acetylides than the linear-backbones. Consequently, a remarkably elevated power factor of 24.9 ± 5.5 μW m−1 K−2 (13 times higher than the linear one) at ambient condition is achieved, which deliver one of the best results among solution-processable organometallic polymeric thermoelectrics.