Optimized Thermoelectric Performance and Plasticity of Ductile Semiconductor Ag₂S_0.5Se_0.5 Via Dual‐Phase Engineering

Abstract

Inorganic semiconductor Ag2S with excellent plasticity is highly desired in flexible and wearable thermoelectrics. However, the compromise between plasticity and thermoelectric performance limits the advances in Ag2S‐based thermoelectric materials and their devices. Here, a 0.5 mol.% Ag2Te‐alloyed Ag2S0.5Se0.5 bulk material is designed, which has a competitively high near‐room‐temperature figure of merit of ≈0.43 at 323 K and an ultra‐high bending strain of ≈32.5% without cracks. Introducing Ag2Te can optimize the carrier concentration and mobility of the Ag2S0.5Se0.5 matrix due to its metal‐like conducting features, leading to a maximum power factor of ≈6 µW cm−1 K−2. Simultaneously, Ag2Te induces Ag‐poor amorphous phase boundaries, serving as buffer layers to enhance the overall plasticity. Moreover, such amorphous phase boundaries combined with multiscale phonon scattering sources can significantly suppress the lattice thermal conductivity to ≈0.28 W m−1 K−1 at 323 K, leading to a high figure of merit. This study demonstrates an innovative route to simultaneously boost the thermoelectric performance and plasticity of ductile semiconductors.

Hidden structures: a driving factor to achieve low thermal conductivity and high thermoelectric performance

“…So far, a number of cutting-edge superionic TE materials have been identified and developed with exceptionally low κ lat and superior TE performance, with the maximum z T s reaching 2.0 or above, e.g. , AgCrSe 2 , 28 CuCrSe 2 , 305,306 InTe, 140,292 Ag 2 (S, Se, Te), 307–312 Cu 2− δ (S, Se, Te), 27,29,313–321 Cu or Ag-based argyrodites, 322–326 AgCuTe, 327 etc. Experimental characterization through X-ray or neutron PDF analysis to probe the subtle structural disorders and atomic dynamics provides a basis for understanding ultralow thermal conductivity in such PLECs.…”

Weavable thermoelectrics: advances, controversies, and future developments

“…However, similar to conductive polymers, carbon materials exhibit relatively low S. Inorganic bulk thermoelectric materials with high σ and S are already in practical use. However, they lack the flexibility to a great extent, although some flexible inorganic films [93,103,104] and ductile semiconductors [94,[105][106][107][108] have been explored. Besides, nano-structuring inorganic semiconductor materials can effectively enhance their flexibility [67,109].…”

Precipitation enhancement of liquid thermoelectric conversion with Fe(ClO4)2/Fe(ClO4)3 dissolved in DMF

“…In recent years, research and development of energy harvesting technologies 1–3 have been vigorously carried out to achieve the sustainable development goals (SDGs) and prevent global warming by reducing CO 2 . Among the energy harvesting technologies, liquid thermoelectric conversion devices (LTEs), which have a simple device structure composed of low-cost materials, are attracting attention.…”