Solution-Synthesis and Processing of Sn-and Bi-Doped Cu 3 SbSe 4 Nanocrystals , Nanomaterials and Ring-Shaped Thermoelectric Generators

Copper-based chalcogenides, comprising abundant, low-cost, and environmental friendly elements, are excellent materials for several energy conversion applications, including photocatalysis, electrocatalysis, photovoltaics and thermoelectrics. In such applications, the production of either crystalline thin films or bulk nanomaterials with high surface area or high relative density by solutionprocessed nanocrystals (NCs) provides several potential advantages, such as high material yield and throughput and composition control with unmatched spatial resolution and low cost. Here we report on the production of Cu3SbSe4 (CASe) NCs with tuned amounts of Sn 4+ and Bi dopants. After proper ligand removal, as monitored by nuclear magnetic resonance and infrared spectroscopies, these NCs were used as building blocks to produce dense CASe bulk nanomaterials for solid state thermoelectric (TE) energy conversion. By adjusting the amount of extrinsic dopants, dimensionless TE figures of merit (ZT) up to 1.26 at 673 K were obtained. Such high ZT values are related to an optimized carrier concentration by proper doping, a minimized lattice thermal conductivity due to efficient phonon