Beschreibung:
The lower thermoelectric performance of n-type PbSe at low temperatures hinders its real application and need to be overcome. Here, a significant enhancement of thermoelectric performance in n-type (PbSe)100- x :(Ag) x (x = 0−30) films was achieved at low temperature. For the (PbSe)75:(Ag)25, the carrier concentration enhanced from 2.36×1019 cm-3 to 7.45×1019 cm-3 in the vicinity of the percolation threshold. The high carrier concentration leads to a large average PFavg at the low temperature range of 300−523 K, the maximum PFavg for (PbSe)100- x :(Ag) x samples is ~37.83μW cm-1 K-2, which is about 200% higher than that of pure PbSe films (~19.16 μW cm-1 K-2). In addition, PbSe:Ag2Se:Ag grain boundary and edge dislocation can engender intrinsically low thermal conductivity. The low thermal conductivity leads to a high ZT and the maximum ZT values for (PbSe)75:(Ag)25 samples is ~0.63 at room temperature, which is more than 250% higher than that of pure PbSe films (ZT = 0.25)