We present a complete open-hardware and software materials acceleration platform (MAP) for sonochemical synthesis of nanocrystals using a versatile tool-changing platform (Jubilee) configured for automated ultrasound application, a liquid-handling robot (Opentrons OT2) and a well-plate spectrometer. An automated high-throughput protocol was developed demonstrating the synthesis of CdSe nanocrystals using sonochemistry and different combinations of sample conditions, including precursor and ligand compositions and concentrations. Cavitation caused by ultrasound fields causes local and transient increases in temperature and pressure sufficient to drive the decomposition of organometallic precursors to drive the chemical reaction leading to nanocrystal formation. A total of 625 unique sample conditions were prepared and analyzed in triplicate with an individual sample volume of as little as 0.5 mL, which drastically reduced chemical waste and experimental times. The rapid onset of cavitation and quick dissipation of energy result in fast nucleation with little nanocrystal growth leading to the formation of small nanocrystals or magic-size clusters (MSCs) depending on composition. Using the effective mass approximation, the calculated QD diameters obtained under all our experimental conditions ranged between 1.3 and 2.1 nm, which was also validated with small angle X-ray scattering (SAXS). Polydispersity, QD shape and optical properties largely varied depending on the concentration of ligands present in solution. Statistical analysis of the spectroscopic data corroborates the qualitative relationships observed from the optical characterization of the samples with the model-agnostic SHAP analysis. The complete workflow relies on relatively low-cost and open-source systems. Automation and the reduced volumes also allow for cost-efficient experimentation, increasing the accessibility of this MAP. The high-throughput capabilities of the automated sonication platform, the extensible nature of the Jubilee system, and the modular nature of the protocol, make the workflow adaptable to a variety of future studies, including other nanocrystal design spaces, emulsification processes, and nanoparticle re-dispersion or exfoliation.
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High-throughput and data driven strategies for the design of deep-eutectic solvent electrolytes
Deep eutectic solvents (DESs) are an attractive class of materials with low toxicity, broad commercial availability, low costs and simple synthesis, which allows for tuning of their properties. We develop and demonstrate the use of high-throughput and data-driven strategies to accelerate the investigation of new DES formulations. A cheminformatics approach is used to outline a design space, which results in 3477 hydrogen bond donor (HBD) and 185 quaternary ammonium salt (QAS) molecules identified as good candidate components for DES. The synthesis methodology is then adapted to a high-throughput protocol using liquid handling robots for the rapid synthesis of DES combinations. High-throughput electrochemical characterization and melting point detection systems are used to measure key performance metrics. To demonstrate the new workflow, a total of 600 unique samples are prepared and characterized, corresponding to 50 unique DES combinations at 12 HBD/QAS molar ratios. After synthesis, a total of 230 samples are found liquid at room temperature and further characterized. Several DESs display conductivities above 1 mS cm −1 , with a maximum recorded conductivity of 13.7 mS cm −1 for the combination of acetylcholine chloride (20 mol%) and ethylene glycol. All liquid DES samples show stable potential windows greater than 3 V. We also demonstrate that these DESs are electrochemically limited by viscosity, both in the conductivity and in the limiting processes on their cyclic voltammograms. Comparison with literature reports shows good agreement for properties measured in the high-throughput study, which helps to validate the workflow. This work demonstrates new methods to accelerate the collection of key DES metrics, providing data to formulate robust property prediction models and obtaining insight on interactions between molecular components. Data-driven high-throughput experimentation strategies can accelerate DES development for a variety of applications. Moreover, these approaches can also be extended to tackle other materials challenges with large molecular design spaces.
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- NSF-PAR ID:
- 10326913
- Date Published:
- Journal Name:
- Molecular Systems Design & Engineering
- ISSN:
- 2058-9689
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Deep eutectic solvents (DES) or eutectic mixtures prepared with a chiral component can lead to new chiral solvents with applications that include asymmetric synthesis and chiral light emitting materials. DES have low melting points, because of strong interactions, such as hydrogen bonding, between components of the mixture. Mixtures are prepared with ammonium salts, tetrabutylammonium chloride ([TBA]Cl) and choline chloride ([Ch]Cl), as hydrogen bond acceptor (HBA) and L‐lactic acid, L‐leucic acid, L‐ascorbic acid, R/S‐acetoxypropionic acid, and methyl‐(S)‐lactate as chiral hydrogen bond donors (HBD). Eight combinations of the HBAs and HBDs were prepared, and a racemic mixture of dissymmetric chiral europium complexes was dissolved in the mixtures. The circularly polarized luminescence (CPL) spectra were measured to determine the chiral discrimination by these chiral solvents. The CPL spectra show that the handedness of the chiral HBD is important to the chiral discrimination exhibited. However, the inversion of the sign of the CPL spectra in 1 : 3 [TBA]Cl:L‐lactic acid vs. 1 : 3 [Ch]Cl:L‐lactic acid, and 1 : 1.5 [Ch]Cl:L‐leucic acid vs. 1 : 1 [TBA]Cl:L‐leucic acid shows that the achiral HBA also plays a critical role in the handedness of the chiral discrimination by the chiral solvent.
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D2ME00050D
