Fig. 4: Decoupled carrier-phonon transport and enhanced thermoelectric properties of entropy-engineered thin films.
From: Carrier-phonon decoupling in perovskite thermoelectrics via entropy engineering
a Schematic diagram of tuning A sites and TiO6 octahedrons to decouple the carrier-phonon transport with increasing entropy. The symbols of elements were shown in the insets. b The correlation between the thermal diffusivity (D) and the nominal configuration entropy (Sconfig.). The thermal diffusivity was measured on corresponding unannealed bulks at 923 K for reference. The purple arrow is a guide for the eyes. c The relation between weighted mobility and observed tolerance factor tobs. to explain the structural origin of mobility recovery. The tolerance factor was calculated from the bond length measured by PDF on corresponding bulks for reference. The purple arrow is a guide for the eyes. d The lattice thermal conductivity (κL), weighted mobility (μW), and μW/κL of SLTO, SBLTO, SBCLTO, and SBCPLTO to show the extent of decoupling and effects of different elements when engineering entropy at room temperature. e, f. Temperature-dependent BE (in log scale) (e), μW/κL (f) of entropy-engineered thin films. g Temperature-dependent zT of SBCPLTO, in comparison with other competitive n-type thermoelectric pure oxides12,58,59,60,61,62,100,101,102. The zT measurement was limited by the highest allowed measuring temperature of TDTR. Since the PF and κ are plateau-like with increasing T at high temperatures, the zT was extrapolated to high temperature (dashed red line).
