High‐Throughput Robotic Synthesis and Photoluminescence Characterization of Aqueous Multinary Copper–Silver Indium Chalcogenide Quantum Dots

Abstract

variability of compositions and properties unrivaled by more conventional chalcogenide semiconductor II-VI or IV-VI NCs. [1][2][3][4][5] Multinary compounds such as copper-indium or copper-zinc-tin chalcogenides can be produced with a broad variation in stoichiometry as well as in different phases for the same stoichiometry. They can be subjected to multiple substitutions, such as sulfide for selenide, copper for silver, zinc for many other bications, indium for gallium or antimony, as well as to doping with mono-, bi-, and trivalent cations producing a vast variety of possible compositions and structures. [1][2][3][4][5] Along with the NC itself, the nature of stabilizing surface ligands can be broadly varied providing NCs with additional hydrophobic/hydrophilic, donor/ acceptor, light-emissive/ absorbing properties. [2,3,5,6] In the case of NCs smaller than the Bohr exciton diameter, that is, multinary quantum dots (QDs), considerable variations of electronic and chemical properties can be achieved by varying only the QD size with other parameters (composition, stoichiometry, ligand type) kept constant. [2,3,5,7] The feasibility of a high-throughput robot-assisted synthesis of complex Cu 1-x Ag x InS y Se 1-x (CAISSe) quantum dots (QDs) by spontaneous alloying of aqueous glutathione-capped Ag-In-S, Cu-In-S, Ag-In-Se, and Cu-In-Se QDs is demonstrated. Both colloidal and thin-film core CAISSe and core/shell CAISSe/ZnS QDs are produced and studied by high-throughput semiautomated photoluminescence (PL) spectroscopy. The silver-copper-mixed QDs reveal clear evidence of a band bowing effect in the PL spectra and higher average PL lifetimes compared to the counterparts containing silver or copper only. The photophysical analysis of CAISSe and CAISSe/ZnS QDs indicates a composition-dependent character of the nonradiative recombination in QDs. The rate of this process is found to be lower for mixed copper-silver-based QDs compared to Cu-or Ag-only QDs. The combination of the band bowing effect and the suppressed nonradiative recombination of CAISSe QDs is beneficial for their applications in photovoltaics and photochemistry. The synergy of highthroughput robotic synthesis and a high-throughput characterization in this study is expected to grow into a self-learning synthetic platform for the production of metal chalcogenide QDs for light-harvesting, light-sensing, and lightemitting applications.

High-Throughput Evaluation of Emission and Structure in Reduced-Dimensional Perovskites

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“…A recently reported HTE process utilizing a robot-based arrayed synthesis technique would take over 9 h to synthesize 576 samples prior to characterization. 40 Acceleration and Optimization of New MHP Composition. After validating our HTE workflow by optimizing (4- MeO-PEAI) 2 -PbI 2 , we chose additional MHP precursors to study.…”

“…Combinatorial vapor deposition processes have been used to grow multiple thin films for the rapid screening of new material compositions; however, solution processable MHPs pose new challenges due to their reliance on volatile solvents that have low boiling points . HTE has been employed in the exploration of MHPs, but until now it has been limited to several experiments on a single MHP or to the exploration of a few compositions with minimal processing conditions. − …”

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Autonomous high-throughput computations in catalysis

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