Method for manufacturing silicon bulk thermoelectric conversion material, silicon bulk thermoelectric conversion material, and thermoelectric conversion element

A silicon bulk thermoelectric conversion material comprising a plurality of silicon nanoparticles,

• wherein the plurality of silicon nanoparticles are joined to each other at a portion of a surface,
• pores configured to separate surfaces of the plurality of silicon nanoparticles from each other are arranged in the silicon bulk thermoelectric conversion material,
• the silicon bulk thermoelectric conversion material has a peak at 510 cm-1 or more and 520 cm-1 or less in a Raman spectrum,
• ZT is 0.10 or more at 22° C. or more and 25° C. or less,
• the silicon bulk thermoelectric conversion material has a thermal conductivity of 2.0 W/m·K or more and 9.0 W/m·K or less,
• in a case where the silicon bulk thermoelectric conversion material has thermal conductivity of 2.0 W/m·K or more and less than 3.0 W/m·K, a longitudinal wave sound velocity is 5,300 m/s or less, and a transverse wave sound velocity is 3,400 m/s or less,
• in a case where the silicon bulk thermoelectric conversion material has thermal conductivity of 3.0 W/m·K or more and less than 4.0 W/m·K, a longitudinal wave sound velocity is 6,100 m/s or less, and a transverse wave sound velocity is 3,700 m/s or less, and
• in a case where the silicon bulk thermoelectric conversion material has thermal conductivity of 4.0 W/m·K or more and 9.0 W/m·K or less, a longitudinal wave sound velocity is 6.400 m/s or less, and a transverse wave sound velocity is 4,200 m/s or less.