@article{21001,
  abstract     = {Copper chalcogenides offer high charge mobility and low lattice thermal conductivity but suffer from structural instability due to dynamic Cu+ migration. Here, we report a colloidal hot-injection synthesis of ternary cesium copper selenide (CsCu5Se3) nanocrystals (NCs), achieving precise control over phase, size, and morphology through tailored precursor-ligand modulation. This strategy enabled systematic exploration of stable and metastable Cs–Cu–Se phases and mechanistic investigation of nucleation and growth, providing insight into phase modulation and dimensional control at the nanoscale. CsCu5Se3 NCs exhibit low lattice thermal conductivity (∼0.5 Wm–1K–1) and an experimental zT of 0.27 at 718 K. Complementary first-principles calculations, consistent with experimental electronic and optical responses, predict a zT of 1.05 at 1000 K. These findings elucidate the formation dynamics of CsCu5Se3 and establish ABZ (A = alkali, B = metal, Z = chalcogen) NCs as tunable platforms for advanced functional applications.},
  author       = {Patil, Niraj Nitish and Wu, Ruiqi and Fiedler, Christine and Kapuria, Nilotpal and Nan, Bingfei and Navita, Navita and Cabot, Andreu and Ibáñez, Maria and Ryan, Kevin M. and Ganose, Alex M. and Singh, Shalini},
  issn         = {2380-8195},
  journal      = {ACS Energy Letters},
  number       = {1},
  pages        = {481--488},
  publisher    = {American Chemical Society},
  title        = {{Layered alkali-copper selenides: Deciphering thermoelectric properties and reaction pathways for nanostructuring β-CsCu5Se3}},
  doi          = {10.1021/acsenergylett.5c02909},
  volume       = {11},
  year         = {2026},
}

@article{22734,
  abstract     = {Silver selenide (Ag2Se) is a promising near-room-temperature thermoelectric material, but its narrow stoichiometric window and β–α phase transition complicate reproducible microstructure control. Here, we present a mismatch-assisted microstructure engineering strategy in which Ag2Se particles are treated with polyanionic ZnSe complexes and consolidated through the β–α transition to introduce ZnSe nanoprecipitates, Ag2Se/ZnSe interfaces, and local strain fields. The crystallographic mismatch between ZnSe and Ag2Se, together with the Zn2+/Ag+ size difference, amplifies phase-transition-induced deformation and promotes high-density dislocations with periodic strain modulations. This defect architecture suppresses grain coarsening, removes excess Ag, limits Ag-interstitial formation, and reduces lattice thermal conductivity through lattice softening and multiscale phonon scattering. Ag2Se–4%ZnSe nanocomposites achieve a peak zTmax of 1.13 at 369 K and a zTavg of 1.08 from 300 to 380 K, demonstrating mismatch-driven defect engineering through the β–α phase transition as a route for optimizing Ag2Se-based thermoelectrics.},
  author       = {Liu, Yu and Kleinhanns, Tobias and Spadaro, Maria Chiara and Genç, Aziz and Horta, Sharona and Navita, Navita and Costanzo, Tommaso and Dutkiewicz, Ewelina and Arbiol, Jordi and Hong, Min and Ibáñez, Maria},
  issn         = {2380-8195},
  journal      = {ACS Energy Letters},
  number       = {8},
  pages        = {5752--5762},
  publisher    = {American Chemical Society},
  title        = {{Exploiting mismatch strain and the β–α phase transition for microstructural engineering in thermoelectric Ag2Se}},
  doi          = {10.1021/acsenergylett.6c01499},
  volume       = {11},
  year         = {2026},
}

@article{22967,
  abstract     = {Alkali salts are widely used in solution processing, yet the corresponding cations are often assumed to remain in the liquid phase. Here, we show that alkali ions introduced during the solution synthesis of SnSe are retained through particle isolation and continue to influence the material during subsequent thermal processing, where they shape the evolution of the final polycrystalline material. Different SnSe powders were prepared using Li+, Na+, and K+ precursors, as well as tetramethylammonium (TMA+) precursors as a nonalkali reference for comparison, and all samples were consolidated under identical conditions. Although all three alkali ions were found in the matrix, at grain boundaries, and in segregated nanoscale regions, they partitioned differently and resulted in distinct grain sizes, defect distributions, and therefore transport properties. Li induced the strongest grain size heterogeneity and the lowest energy barriers, Na the best overall balance between carrier concentration and mobility, and K the broadest alkali-rich grain boundary regions along with the strongest interfacial penalty to charge carrier transport. These results show that residual alkali ions are not just remnants of solution synthesis but active determinants of microstructure and thermoelectric performance in SnSe.},
  author       = {Fiedler, Christine and Horta, Sharona and Navita, Navita and Maji, Krishnendu and Kleinhanns, Tobias and Llorca, Jordi and Wang, Qi and Ramon, Maria Garcia and Das, Sambit and Gavini, Vikram and Liu, Yu and Ibáñez, Maria},
  issn         = {1520-5002},
  journal      = {Chemistry of Materials},
  number       = {18},
  pages        = {9323–9332},
  publisher    = {American Chemical Society},
  title        = {{Alkali ions retained from synthesis govern microstructure and transport in solution-processed SnSe}},
  doi          = {10.1021/acs.chemmater.6c01284},
  volume       = {38},
  year         = {2026},
}

@article{15166,
  abstract     = {Reducing defects boosts room-temperature performance of a thermoelectric device},
  author       = {Navita, Navita and Ibáñez, Maria},
  issn         = {1095-9203},
  journal      = {Science},
  number       = {6688},
  pages        = {1184},
  publisher    = {American Association for the Advancement of Science},
  title        = {{Electron highways are cooler}},
  doi          = {10.1126/science.ado4077},
  volume       = {383},
  year         = {2024},
}