Experimental and theoretical evaluation on thermoelectricity for SPS-joined p-n module in Bi-Te system

Thermoelectric p-n modules are prepared by the spark plasma sintering (SPS) solid bonding for experimental and theoretical evaluation on their thermoelectricity. Both p-type (Bi _0.4Sb _1.6Te ₃) and n-type (Bi ₂Te _2.85Se _0.15) materials are prealloyed from elemental granule mixture via the bulk mechanical alloying, shear-extruded to control their anisotropic texture and joined to fabricate p-n modules. The mutual atomic diffusion layer across the p-n interface is controlled down to 2 μm, 0.04 times narrower than that for hot-pressed p-n interface. Open-circuit voltage and resistance of p-n modules are measured for various interface layer height. They are compared with theoretical estimates via the computer-aided analysis. Analytical expressions are proposed to estimate the thermoelectric characteristics on p-n module. The power generation characteristics of p-n modules is also evaluated for various temperature differences between cold and hot sources.