Transparent charge transfer complex with high thermoelectric performance

Searching for high-performance n-type organic thermoelectric mate-rials with good air stability and high transparency remains a big chal-lenge. Here, we report an all-transparent n-type charge transfer com-plex [ZnBr2(Br-C6H4-NH2)2] with a wide band gap of 4.25 eV. This material exhibits a high electrical conductivity of ?2,936 S cm -1 and Seebeck coefficient of -114 mV K-1, leading to an extraordinarily high power factor of 3,797 mW m-1 K-2 at room temperature-this is a record value for organic thermoelectric materials. Remarkably, figure of merit (ZT) values of 0.23 at 298 K and 0.45 at 473 K were achieved. These ZT values offer state-of-the-art performance for-type organic materials that are superior to typical inorganic mate-rials when operating at near room temperature. The high thermoelectric performance is attributed to the electron-transfer-induced n-type heavily doped characteristic, high valley band degeneracy, and heavy effective mass. This work will promote the development of organic thermoelectric materials.