| 초록 |
Because the nearly identical conduction bands, isostructural PbSe is a promising Te-free n-type alternative to PbTe for medium-temperature range power generation. However, its power factor lies far below PbTe. Here, we reveal the ultrahigh power factor of PbSe by concurrently introducing excess Cu to its interstitial void and Te doping to the lattice. Atom probe tomography confirms a strong attraction between interstitial Cu and Te dopants. It electrically links Cu to the PbSe lattice and markedly displace Pb atom from its octahedral center. These effects enhanced the carrier concentration without reducing the carrier mobility and flattened the conduction band edge, which simultaneously improved Seebeck coefficient and electrical conductivity. The power factor for Cu0.005PbSe0.99Te0.01 reaches to 30 μW cm−1 K−2 at 300 K and slightly decreases to 23 μWcm−1 K−2 at 773 K with an average value of ~27 μW cm−1 K−2. These are record values among all reported n-type Te-free materials. |
