Thiol Amine Research Articles

Porous Ag2Se Fabricated by a Modified Cold Sintering Process with the Average zT Around Unity Near Room Temperature

AbstractSilver selenide (Ag2Se) is a promising material for thermoelectric applications near room temperature. This work proposes a new fabrication route for bulk Ag2Se via a modified cold sintering process (mCSP) to enhance its figure‐of‐merit (zT). Unlike conventional CSP, mCSP employs thiol‐amine (TA) as a liquid medium that completely undissolves Ag2Se, leading to a free flow of the TA solution within interparticle channels. By sintering at temperatures above the boiling point of TA, the liquid evaporates, leaving behind a bulk Ag2Se material with a tube‐like porous structure (open pores). These induced defects strongly influence thermoelectric properties of Ag2Se, with a substantial increase in the Seebeck coefficient and decrease in electrical conductivity. The overall power factor of the mCSP sample with TA surpasses that of the control sample without TA, consistent with effective band modeling of Ag2Se. Moreover, the created micropores during mCSP effectively suppresses the thermal conductivity, leading to a maximum zT above 1.0 at 400 K by optimizing mCSP parameters. Importantly, the average zT within the 300–400 K range is around unity, representing one of the highest reported values. Further optimization of mCSP parameters can enhance average zT beyond unity, making Ag2Se more competitive with state‐of‐the‐art materials near room temperature.

Visualizing Drug Release from a Stimuli-Responsive Soft Material Based on Amine-Thiol Displacement.

In this research, we developed a photoluminescent platform using amine-coupled fluorophores, generated from a single conjugate acceptor containing bis-vinylogous thioesters. Based on the experimental and computational results, the fluorescence turn-on mechanism was proposed to be charge separated induced energy radiative transition for the amine-coupled fluorophore, while the sulfur-containing precursor was not fluorescent since the energy internal conversion occurred through vibrational 2RS- (R represents alkyl groups) as energy acceptor(s). Further utilizing the conjugate acceptor, we establish a new fluorogenic approach via a highly cross-linked soft material to selectively detect cysteine under neutral aqueous conditions. Turn-on fluorescence emission and macroscopic degradation occurred in the presence of cysteine as the stimuli, which can be visually tracked due to the generation of an optical indicator and the cleavage of linkers within the matrix. Furthermore, a novel drug delivery system was constructed, achieving controlled release of sulfhydryl drug (6-mercaptopurine) which was tracked by photoluminescence and high-performance liquid chromatography. The photoluminescent molecules developed herein are suitable for visualizing polymeric degradation, making them suitable for additional "smart" material applications.

Fluorometric detection of volatile amines using an indanonalkene platform

An “indanonalkene” fluorescent chemosensor captured volatile amines via an amine–thiol scrambling reaction, and was applied to prepare portable paper-based sensors and polymeric film sensors for point-of-care detection of amines.

Polymorphic Control of Solution-Processed Cu2SnS3 Films with Thiol-Amine Ink Formulation.

There is increasing demand for tailored molecular inks that produce phase-pure solution-processed semiconductor films. Within the Cu–Sn–S phase space, Cu2SnS3 belongs to the I2–IV–VI3 class of semiconductors that crystallizes in several different polymorphs. We report the ability of thiol–amine solvent mixtures to dissolve inexpensive bulk Cu2S and SnO precursors to generate free-flowing molecular inks. Upon mild annealing, polymorphic control over phase-pure tetragonal (I4̅2m) and orthorhombic (Cmc21) Cu2SnS3 films was realized simply by switching the identity of the thiol (i.e., 1,2-ethanedithiol vs 2-mercaptoethanol, respectively). Polymorph control is dictated by differences in the resulting molecular metal–thiolate complexes and their subsequent decomposition profiles, which likely seed distinct Cu2–xS phases that template the ternary sulfide sublattice. The p-type tetragonal and orthorhombic Cu2SnS3 films possess similar experimental direct optical band gaps of 0.94 and 0.88 eV, respectively, and strong photoelectrochemical current responses. Understanding how ink formulation dictates polymorph choice should inform the development of other thiol–amine inks for solution-processed films.

Solution Phase Growth and Ion Exchange in Microassemblies of Lead Chalcogenide Nanoparticles.

We demonstrate the synthesis of micron-sized assemblies of lead chalcogenide nanoparticles with controlled morphology, crystallinity, and composition through a facile room-temperature solution phase reaction. The amine–thiol solvent system enables this synthesis with a unique oriented attachment growth mechanism of nanoparticles occurring on the time scale of the reaction itself, forming single-crystalline microcubes of PbS, PbSe, and PbTe materials. Increasing the rate of reaction by changing reaction parameters further allows disturbing the oriented attachment mechanism, which results in polycrystalline microassemblies with uniform spherical morphologies. Along with polycrystallinity, due to the differences in reactivities of each chalcogen in the solution, a different extent of hollow-core nature is observed in these microparticles. Similar to morphologies, the composition of such microparticles can be altered through very simplistic room-temperature solution phase coprecipitation, as well as ion-exchange reactions. While coprecipitation reactions are successful in synthesizing core–shell microstructures of PbSe–PbTe materials, the use of solution phase ion-exchange reaction allows for the exchange of not only Te with Se but also Ag with Pb inside the core of the PbTe microparticles. Despite exchanging one Pb with two Ag cations, the hollow-core nature of particles aids in the retention of the original uniform microparticle morphology.

Synthesis of thiol amine surfactant for sensor fabrication to determine chromium(III) ions in different water samples

A thiol amine surfactant, poly-3-(dodecylthio)-N-hexadecylacrylamide (iphI) was prepared and characterized using spectral methods of analyses. The proposed potentiometric method was based on the fabrication of iphI-modified carbon paste (iphI-MCPE; electrode IV) sensor. Fast, highly sensitive and wide dynamic range potentiometric sensor was constructed using the prepared ionophore to quantify Cr(III) ions in spiked water sample under optimum conditions. The electrode (IV) exhibited an excellent Nernstian response to Cr(III) ion ranging from 4.8 × 10-7 to 1.0 × 10-2 mol L-1 with a detection limit of 4.8 × 10-7 mol L-1 and a slope of 19.59±0.45 mV decade-1 over a wide pH range (2.0-8.0) with a fast response time (7 s) at 25 oC. The proposed sensor showed fairly good discriminating ability towards Cr(III) ion in comparison with many hard and soft metal ions. The developed electrode has been successfully applied for the Cr(III) ions potentiometric determination in different water samples. The results obtained compared well with those obtained using atomic absorption spectrometry.

Analyzing and Tuning the Chalcogen-Amine-Thiol Complexes for Tailoring of Chalcogenide Syntheses.

The amine-thiol solvent system has been used extensively to synthesize metal chalcogenide thin films and nanoparticles because of its ability to dissolve various metal and chalcogen precursors. While previous studies of this solvent system have focused on understanding the dissolution of metal precursors, here we provide an in-depth investigation of the dissolution of chalcogens, specifically Se and Te. Analytical techniques, including Raman, X-ray absorption, and NMR spectroscopy and high-resolution tandem mass spectrometry, were used to identify pathways for Se and Te dissolution in butylamine-ethanethiol and ethylenediamine-ethanethiol solutions. Se in monoamine-monothiol solutions was found to form ionic polyselenides free of thiol ligands, while in diamine-monothiol solutions, thiol coordination with polyselenides was predominately observed. When the relative concentration of thiol is increased to that of Se, the chain length of polyselenide species was observed to shorten. Analysis of Te dissolution in diamine-thiol solutions also suggested the formation of relatively unstable thiol-coordinated Te ions. This instability of Te ions was found to be reduced by codissolving Te with Se in diamine-thiol solutions. Analysis of the codissolved solutions revealed the presence of atomic interaction between Se and Te through the identification of Se-Te bonds. This new understanding then provided a new route to dissolve otherwise insoluble Te in butylamine-ethanethiol solutions by taking advantage of the Se2- nucleophile. Finally, the knowledge gained for chalcogen dissolutions in this solvent system allowed for controlled alloying of Se and Te in PbSenTe1-n material and also provided a general knob to alter various metal chalcogenide material syntheses.

Solution processed CZTS solar cells using amine–thiol systems: understanding the dissolution process and device fabrication

The dissolution process of CZTS constituent elements in a low-toxicity amine-thiol solvent system is analysed in detail through the use of ESI-MS and IRMPD techniques. Devices produced from this solution achieved efficiencies of up to 8.1%.

Investigating Chemistry of Metal Dissolution in Amine–Thiol Mixtures and Exploiting It toward Benign Ink Formulation for Metal Chalcogenide Thin Films

Solution processing of metal chalcogenides using elemental metals dissolved in an amine–thiol solvent mixture has recently received a great deal of attention for the fabrication of thin-film optoelectronic devices. However, little is known about the dissolution pathway for metallic precursors in such mixtures. To exploit the full potential of this method, it is essential that a detailed understanding of the dissolution chemistry be developed. In this study, we use several characterization techniques to examine these solutions and then propose reaction mechanisms for In and Cu dissolutions in a hexylamine/1,2-ethanedithiol mixture. These dissolutions are rather found to be reactions resulting in metal oxidation with coevolution of H2 forming bis(1,2-ethanedithiolate)indium(III) in the case of indium dissolution and high nuclearity Cu(I) thiolate compounds in case of copper dissolution. This understanding allowed us to address the issue of toxicity and corrosivity associated with amine–thiol solvent by util...

Lead Chalcogenide Nanoparticles and Their Size-Controlled Self-Assemblies for Thermoelectric and Photovoltaic Applications

We report a facile, room temperature synthesis of PbS, PbSe, PbSxSe1–x, and PbTe nanoparticles and their microscale assemblies by combining a chalcogen solution and a lead halide solution in select thiol–amine mixtures. Selection of an appropriate thiol–amine pair and/or the use of appropriate amine to thiol ratio has demonstrated a size control on nanoparticle self-assemblies ranging from nano- to microscale. Proper washing of these particles has yielded phase-pure and compositionally uniform material with minimal or no presence of any carbonaceous ligands on the particle surface, making it attractive for electronic device fabrication. The resulting PbS material exhibits bandgaps in the range 0.6 eV to as high as 1.2 eV for various assembly sizes. These optical bandgaps confirm the retention of quantum confinement of PbS material even in self-assembled nano/microstructures, which could be an interesting phenomenon for future photovoltaic development. Along with carbon-free, quantum-confined self-assemblies, this chemistry also provides a room temperature and instantaneous reaction route to synthesize individually dispersed PbS and PbSe particles with long chain ligand capping similar to traditional synthesis routes. The PbSe material synthesized from this route shows the ability to alloy with PbS at room temperature in the entire composition range and also demonstrates thermoelectric performance comparable to results in existing undoped PbSe literature.

Deposition and application of a Mo–N back contact diffusion barrier yielding a 12.0% efficiency solution-processed CIGS solar cell using an amine–thiol solvent system

The use of a Mo–N barrier for solution-processed CIGS results in reduced MoSe2 formation. This enabled longer selenization time, enhanced grain growth and performance.

Thiolactone-Functional Reversible Deactivation Radical Polymerization Agents for Advanced Macromolecular Engineering

The development of innovative, easy to implement strategies for polymer synthesis and modification contributes to pushing back the limits of macromolecular engineering. In this context, thiolactones were highlighted as a new powerful “click” strategy involving an amine–thiol–ene conjugation. In order to further explore the potential of thiolactone chemistry for the field of reversible-deactivation radical polymerization (RDRP), we have developed a toolbox of γ-thiolactone-based RDRP agents including xanthates, bromides, and an alkoxyamine. These RDRP agents were used for the polymerization of more activated and less activated monomers using appropriate RDRP techniques such as RAFT/MADIX, ATRP, and NMP. Well-defined thiolactone-terminated polymers were obtained and characterized for different degrees of polymerizations. An example of thiolactone–telechelic PNIPAM using a thiolactone-based xanthate and an ω-end-chain cyclization strategy was reported. The great reactivity of the thiolactone end-group for po...

Preparation of electrocatalysts using a thiol-amine solution processing method.

Solution processing has emerged as a promising option for the preparation of functional materials with methods that tend to be cheap, less energy intensive, and allow for high throughput and large area deposition. A recently developed method, whereby a binary thiol-amine solvent mixture is used to dissolve bulk oxides, chalcogenides, or elemental materials to yield molecular precursor inks for the deposition of phase pure chalcogenide materials, has recently garnered attention for applications in optoelectronics, thermoelectrics, and electrocatalysis. Presented here is a summary of reports on the application of this "alkahest" method for the deposition of electrocatalytic materials. Ink formulations drawing on the vast library of bulk precursor solutes have already resulted in a large collection of synthesized functional materials, with room still to explore new, or less studied, materials. Additionally, as is seen for the electrocatalysts, engineering of inks and deposition procedures can lead to higher performance through optimized morphology and form factors.

Asymmetric [4+2] annulations to construct norcamphor scaffolds with 2-cyclopentenone via double amine-thiol catalysis.

An efficient double catalytic system, combining chiral amine and 2-mercaptobenzoic acid, is applied for α',β-regioselective [4+2] annulations of 2-cyclopentenone with a diversity of activated alkenes, constructing multifunctional chiral bicycle[2,2,1]heptane scaffolds in good to excellent yields and enantioselectivities. In comparison with the traditional cross-dienamine species between 2-cyclopentenone and chiral amine, the interrupted enamine intermediate containing a covalently linked thiol catalyst shows significantly improved reactivity.

Precursors for PbTe, PbSe, SnTe, and SnSe synthesized using diphenyl dichalcogenides.

We create precursors for PbTe, PbSe, SnTe, and SnSe by reacting Pb or Sn with diphenyl dichalcogenides in a variety of different solvents. We then deposit PbSexTe1-x thin films using these precursors and measure their thermoelectric properties. Introducing Na-dopants into the films allows the thermoelectric properties to be varied.

Facile synthesis and hydrazine detection activity of Sb2S3 films on indium tin oxide electrode

Antimony sulfide (Sb2S3) films on indium tin oxide (ITO) glass substrates were prepared by electrodeposition method followed with heat-treatment process using a thiol–amine as solvent mixture under ambient conditions. The structure and properties of the Sb2S3 films were characterized by XRD, SEM, TEM and electrochemical workstation. The results show Sb2S3 films mainly consist of orthorhombic phase with micro-nanorods morphology. Sb2S3 films exhibit good electrocatalytic activity towards hydrazine oxidation with a low detection limit of 0.4 μM. The facile synthesis method and excellent sensing properties make the Sb2S3 films as a promising candidate for potential application in the field of catalysis and environmental.

Straightforward Xanthate-Mediated Synthesis of Functional γ-Thiolactones and Their Application to Polymer Synthesis and Modification

Thiolactones allow catalyst-free polymer synthesis and modification under stoichiometric conditions at mild temperatures, without the need for tedious and costly purification steps. However, there is a need for simple and general methods for the preparation of functional thiolactones. We have developed a modular platform for γ-thiolactone synthesis based on free-radical xanthate addition to alkenes. Because of the ready availability of a great variety of functional vinyl, allyl, and maleimido derivatives, numerous substituents (exemplified here through alkyl, perfluoroalkyl, diethyl phosphonate, and N-substituted succinimidyl groups) could be efficiently attached to the γ-position of the thiolactone ring. A second substituent may be added in the α-position by proper selection of the xanthate leaving group. In all cases the target thiolactone was obtained in good yield from the xanthate:alkene monoadduct by consecutive Chugaev elimination and cyclization. The potential of these new substituted thiolactone building blocks for polymer chemistry was demonstrated via an amine–thiol–ene conjugation strategy which resulted in successful end-functionalization of amino-terminated polymers and a thiol–acrylate step-growth polymerization to prepare functional poly(ester amide)s. This versatile method for making functional thiolactones should find broad applications as a means to prepare new materials with original properties.

Facile synthesis of thermo-, pH-, CO2- and oxidation-responsive poly(amido thioether)s with tunable LCST and UCST behaviors

Multi-responsive N-substituted poly(amido thioether) copolymers synthesized by one-pot amine–thiol–acrylate polyaddition could exhibit composition-dependent and stimuli-triggered single or double thermoresponsivity.

Method for the Solution Deposition of Phase-Pure CoSe2 as an Efficient Hydrogen Evolution Reaction Electrocatalyst

We demonstrate the ability of a thiol–amine solvent mixture to deposit phase-pure marcasite-type CoSe2 nanostructured thin films as effective hydrogen evolution reaction (HER) electrocatalysts. Electrodes are readily prepared by spin coating a precursor ink onto highly ordered pyrolytic graphite substrates followed by annealing to 350 °C. The resulting CoSe2 films have an onset potential for HER of −117 mV vs RHE and Tafel slopes of ca. 60 mV dec–1. Normalization based on electrochemically active surface area reveals that simple optimization of film thickness, based on the number of layers deposited, leads to electrodes with better surface utilization. Based on the electrocatalytic performance of the solution-processed CoSe2 presented here (η10mA/cm2 = −272 mV vs RHE), this approach shows promise as a simple method to deposit a wide range of useful dichalcogenide electrocatalysts.

Dissolution of Sn, SnO, and SnS in a Thiol-Amine Solvent Mixture: Insights into the Identity of the Molecular Solutes for Solution-Processed SnS.

Binary solvent mixtures of alkanethiols and 1,2-ethylenediamine have the ability to readily dissolve metals, metal chalcogenides, and metal oxides under ambient conditions to enable the facile solution processing of semiconductor inks; however, there is little information regarding the chemical identity of the resulting solutes. Herein, we examine the molecular solute formed after dissolution of Sn, SnO, and SnS in a binary solvent mixture comprised of 1,2-ethanedithiol (EDT) and 1,2-ethylenediamine (en). Using a combination of solution (119)Sn NMR and Raman spectroscopies, bis(1,2-ethanedithiolate)tin(II) was identified as the likely molecular solute present after the dissolution of Sn, SnO, and SnS in EDT-en, despite the different bulk material compositions and oxidation states (Sn(0) and Sn(2+)). All three semiconductor inks can be converted to phase-pure, orthorhombic SnS after a mild annealing step (∼350 °C). This highlights the ability of the EDT-en solvent mixture to dissolve and convert a variety of low-cost precursors to SnS semiconductor material.