Alkali Ions Retained from Synthesis Govern Microstructure and Transport in Solution-Processed SnSe
Year: 2026
Type: article
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.
Source: Chemistry of Materials
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: U.S. Department of Energy, Institute of Science and Technology Austria, National Energy Research Scientific Computing Center, European Commission, National Natural Science Foundation of China, Generalitat de Catalunya, Novo Nordisk Fonden, Office of Science, Deutsches Elektronen-Synchrotron, European Regional Development Fund, Agencia Estatal de Investigación
Awards: G1175115578, G1286236842, G1537387247, G2064873908, G2102522584, G2262748287, G2265579674, G2462415295, G2601397997, G3005324705, G300979063, G3083819904, G34346518, G3480869486, G354759427, G3562095311, G3681454997, G387506447, G4042783231, G410571670, G419881185, G4228227490, G425668148, G42916606, ISTplus - Postdoctoral Fellowships, G4501827968, G451917667, IST-BRIDGE: International postdoctoral program, G498139845, G5080475149, G5195188938, G526230902, G5967599077, G6033112984, G6652958823, G6895111204, G7001747737, G704498496, G7084143925, G8049466214, G969889393
OpenAlex ID: W7211968231