Epitaxial Electrodeposition Of Ordered Inorganic Materials

Conspectus The quality of technological materials generally improves as the crystallographic order is increased. This is particularly true in semiconductor materials, as evidenced by the huge impact that bulk single crystals of silicon have had on electronics. Another approach to producing highly ordered materials is the epitaxial growth of crystals on a single-crystal surface that determines their orientation. Epitaxy can be used to produce films and nanostructures of materials with a level of perfection that approaches that of single crystals. It may be used to produce materials that cannot be grown as large single crystals due to either economic or technical constraints. Epitaxial growth is typically limited to ultrahigh vacuum (UHV) techniques such as molecular beam epitaxy and other vapor deposition methods. In this Account, we will discuss the use of electrodeposition to produce epitaxial films of inorganic materials in aqueous solution under ambient conditions. In addition to lower capital costs than UHV deposition, electrodeposition offers additional levels of control due to solution additives that may adsorb on the surface, solution pH, and, especially, the applied overpotential. We show, for instance, that chiral morphologies of the achiral materials CuO and calcite can be produced by electrodepositing the materials in the presence of chiral agents such as tartaric acid. Inorganic compound materials are electrodeposited by an electrochemical-chemical mechanism in which solution precursors are electrochemically oxidized or reduced in the presence of molecules or ions that react with the redox product to form an insoluble species that deposits on the electrode surface. We present examples of reaction schemes for the electrodeposition of transparent hole conductors such as CuI and CuSCN, the magnetic material Fe3O4, oxygen evolution catalysts such as Co(OH)2, CoOOH, and Co3O4, and the n-type semiconducting oxide ZnO. These materials can all be electrodeposited as epitaxial films or nanostructures onto single-crystal surfaces. Examples of epitaxial growth are given for the growth of films of CuI(111) on Si(111) and nanowires of CuSCN(001) on Au(111). Both are large mismatch systems, and the epitaxy is explained by invoking coincidence site lattices in which x unit meshes of the film overlap with y unit meshes of the substrate. We also discuss the epitaxial lift-off of single-crystal-like foils of metals such as Au(111) and Cu(100) that can be used as flexible substrates for the epitaxial growth of semiconductors. The metals are grown on a Si wafer with a sacrificial SiOx interlayer that can be removed by chemical etching. The goal is to move beyond the planar structure of conventional Si-based chips to produce flexible electronic devices such as wearable solar cells, sensors, and flexible displays. A scheme is shown for the epitaxial lift-off of wafer-scale foils of the transparent hole conductor CuSCN. Finally, we offer some perspectives on possible future work in this area. One question we have not answered in our previous work is whether these epitaxial films and nanostructures can be grown with the level of perfection that is achieved in UHV. Another area that is ripe for exploration is the epitaxial electrodeposition of metal-organic framework materials from solution precursors

Epitaxial Electrodeposition of Hole Transport CuSCN Nanorods on Au(111) at the Wafer Scale and Lift-Off to Produce Flexible and Transparent Foils

The wide bandgap p-type metal pseudohalide semiconductor copper(I) thiocyanate (CuSCN) can serve as a transparent hole transport layer in various opto-electronic applications such as perovsksite and organic solar cells and light-emitting diodes. The material deposits as one-dimensional CuSCN nanorod arrays, which are advantageous due to their high surface area and good charge transport properties. However, the growth of high-quality epitaxial CuSCN nanorods has remained a challenge. Here, we introduce a low cost and highly scalable room temperature procedure for producing epitaxial CuSCN nanorods on Au(111) by an electrochemical method. Epitaxial CuSCN grows on Au(111) with a high degree of in-plane as well as out-of-plane order with +0.22% coincidence site lattice mismatch. The phase of CuSCN that deposits is a function of the Cu2+/SCN- ratio in the deposition bath. A pure rhombohedral material deposits at higher SCN- concentrations, whereas a mixture of rhombohedral and hexagonal phases deposits at lower SCN- concentrations. A Au/epitaxial CuSCN/Ag diode has a diode quality factor of 1.4, whereas a diode produced with polycrystalline CuSCN has a diode quality factor of 2.1. A highly ordered foil of CuSCN was produced by epitaxial lift-off following a triiodide etch of the thin Au substrate. The 400 nm-thick CuSCN foil had an average 94% transmittance in the visible range and a 3.85 eV direct bandgap

Epitaxial Single-Domain Cu-BTC Metal-Organic Framework Thin Films and Foils by Electrochemical Conversion of Cuprous Oxide

Metal-Organic Frameworks (MOFs) Are an Important Class of Crystalline Porous Materials with Extensive Chemical and Structural Merits. However, the Fabrication of MOF Thin Films Oriented Along All Crystallographic Axes to Achieve Well-Aligned Nanopores and Nanochannels with Uniform Apertures Remains a Challenge. Here, We Achieved Highly Crystalline Single-Domain MOF Thin Films with the [111] Out-Of-Plane Orientation by Electrochemical Conversion of Cuprous Oxide. Copper(II)-Benzene-1,3,5-Tricarboxylate, Cu3(BTC)2 (Referred to as Cu-BTC), is a Well-Known Metal-Organic Open Framework Material with a Cubic Crystal System. Epitaxial Cu-BTC(111) Thin Films Were Manufactured by Electrochemical Oxidation of Cu2O(111) Films Electrodeposited on Single-Crystal Au(111). the Cu-BTC(111) Shows an In-Plane Antiparallel Relationship with the Precursor Cu2O(111) with a −0.91% Coincidence Site Lattice Mismatch. a Plausible Mechanism Was Proposed for the Electrochemical Conversion of Cu2O into Cu-BTC, Indicating Formation of Intermediate CuO, Growth of Cu-BTC Islands, and Termination with Coalesce into a Dense Film with a Limiting Thickness of About 740 Nm. the Faradaic Efficiency for the Electrochemical Conversion Was 63%. in Addition, Epitaxial Cu-BTC(111) Foils Were Fabricated by Epitaxial Lift-Off Following the Electrochemical Etching of Residual Cu2O Underneath the Cu-BTC. It Was Also Demonstrated that Cu-BTC(111) Films with Two In-Plane Domains and Textured Cu-BTC(111) Films Can Be Achieved on a Large Scale using Electrodeposited Au/Si and Au-Coated Glass as Low-Cost Substrates

Epitaxial Electrodeposition of 2D-Layered BiI₃ and Conversion to Highly Ordered Bi-Based Organic-Inorganic Halide-Based Perovskites

Highly-ordered, epitaxial semiconductor thin films have low defect densities and excellent photo-physical properties that are desired for optoelectronic devices. Single crystalline perovskite materials are known to provide lower trap densities, a larger diffusion length, and higher photo-conversion efficiencies in perovskite solar cells. However, the preparation of cost-effective, highly ordered semiconductor films with a uniform surface morphology, low electron-hole recombination, and low trap densities remains a bottleneck to achieve higher device efficiencies in large-area electronics. Electrodeposition is a deposition route that is highly scalable and provides a variety of deposition parameters such as potential, pH, temperature, and additives that can be tuned to produce highly ordered epitaxial films with controlled morphologies. Bismuth triiodide, BiI3, is a 2D-metal halide semiconductor that crystallizes in a R3̅ (H) space group symmetry with lattice parameters of a = b = 0.7516 nm, c = 2.0718 nm. BiI3 possesses a structure with repeating units of the I-Bi-I plane, in which a monolayer of Bi atoms is sandwiched between two layers of iodide with strong Bi-I ionic bonds. We deposited epitaxial BiI3 films on Au(111) substrate electrochemically by reducing I2 in the presence of Bi3+. The epitaxial films of the solar light-absorbing perovskite (CH3NH3)3Bi2I9 are produced in a solution from BiI3 by topotactic transformation

Epitaxial Electrodeposition of BiI3 and Topotactic Conversion to Highly Ordered Solar Light-Absorbing Perovskite (CH₃NH₃)₃Bi₂I₉

Highly ordered, epitaxial semiconductor thin films have low defect densities and excellent photophysical properties that are desired for optoelectronic devices. In this work, the epitaxial films of BiI3 are electrodeposited onto Au(111) substrates, and these films are removed by epitaxial lift-off to produce free-standing, single-crystal-like foils of BiI3. The two-dimensional (2D) layering of the BiI3 van der Waals solid allows for the epitaxial lift-off, and it provides a pathway to producing other important materials. The epitaxial films of the solar light-absorbing perovskite (CH3NH3)3Bi2I9 are produced in a solution from BiI3 by topotactic transformation. Epitaxially grown BiI3 shows a 2D-nanodisc-like morphology and highly ordered [001] out-of-plane orientation having the epitaxial relationship with the substrate as BiI3(0001)[1̅1̅20 ± 3°]//Au(111)[1̅1̅2], determined by X-ray pole figures. The lattice mismatch is minimized by the (±)3° rotation of the film relative to the substrate. The X-ray rocking curve shows that single crystal like BiI3 has a mosaic spread with full width at half-maximum (FWHM) of about ∼0.69°. The topotactic transformation of BiI3 produces a highly ordered [001]-oriented epitaxial perovskite (CH3NH3)3Bi2I9

Analyses of MYMIV-induced transcriptome in Vigna mungo as revealed by next generation sequencing

Mungbean Yellow Mosaic Virus (MYMIV) is the viral pathogen that causes yellow mosaic disease to a number of legumes including Vigna mungo. VM84 is a recombinant inbred line resistant to MYMIV, developed in our laboratory through introgression of resistance trait from V. mungo line VM-1. Here we present the quality control passed transcriptome data of mock inoculated (control) and MYMIV-infected VM84, those have already been submitted in Sequence Read Archive (SRX1032950, SRX1082731) of NCBI. QC reports of FASTQ files generated by ‘SeqQC V2.2’ bioinformatics tool. Keywords: Vigna mungo, Transcriptome, Annotation, Recombinant inbred line

Epitaxial Electrodeposition of Hole Transport CuSCN Nanorods on Au(111) at the Wafer Scale and Lift-Off to Produce Flexible and Transparent Foils

The wide bandgap p-type metal pseudohalide semiconductor copper(I) thiocyanate (CuSCN) can serve as a transparent hole transport layer in various opto-electronic applications such as perovsksite and organic solar cells and light-emitting diodes. The material deposits as one-dimensional CuSCN nanorod arrays, which are advantageous due to their high surface area and good charge transport properties. However, the growth of high-quality epitaxial CuSCN nanorods has remained a challenge. Here, we introduce a low cost and highly scalable room temperature procedure for producing epitaxial CuSCN nanorods on Au(111) by an electrochemical method. Epitaxial CuSCN grows on Au(111) with a high degree of in-plane as well as out-of-plane order with +0.22% coincidence site lattice mismatch. The phase of CuSCN that deposits is a function of the Cu2+/SCN- ratio in the deposition bath. A pure rhombohedral material deposits at higher SCN- concentrations, whereas a mixture of rhombohedral and hexagonal phases deposits at lower SCN- concentrations. A Au/epitaxial CuSCN/Ag diode has a diode quality factor of 1.4, whereas a diode produced with polycrystalline CuSCN has a diode quality factor of 2.1. A highly ordered foil of CuSCN was produced by epitaxial lift-off following a triiodide etch of the thin Au substrate. The 400 nm-thick CuSCN foil had an average 94% transmittance in the visible range and a 3.85 eV direct bandgap

Epitaxial Electrodeposition of Cu(111) onto an lCysteine Self-Assembled Monolayer on Au(111) and Epitaxial Lift-Off of Single-Crystal-like Cu Foils for Flexible Electronics

Functional self-assembled monolayers (SAMs) of thiols on single-crystal metals provide two-dimensional (2D) soft templates for the highly ordered growth of crystalline materials. An epitaxial Cu(111) film is electrodeposited on a SAM of the amino acid l-cysteine on Au(111). Epitaxy is confirmed, with Cu(111) following the Au(111) in-plane and out-of-plane orientations with a small amount of twinned [511] orientation, which is shown by X-ray analysis. The mismatch between Cu(111) and the Au(111) substrate is −11.37%. This mismatch is lowered to −0.29% by forming a coincident site lattice in which nine unit meshes of Cu coincide with eight unit meshes of Au. Defect-mediated and coordination-controlled electrodeposition mechanisms are illustrated as two possible deposition mechanisms. The carboxylic (−COOH) and amine (−NH2) functional groups of the l-cysteine molecule are shown to be crucial for the epitaxy of Cu because a 1-butanethiol SAM on Au(111) which has no functional groups yields a textured film with no in-plane order. The (√3 × √3)R30° surface structure of l-cysteine SAM and the c(4 × 2) surface structure of 1-butanethiol SAM on Au(111) are discussed. A 3D model of the Cu lattice on the l-cysteine SAM on Au(111) is proposed. A possible coordination to Cu is shown, which facilitates the epitaxial nucleation and 2D growth of Cu. The Cu(111) films have potential as a substrate for catalysts for CO2 reduction, photovoltaic devices, spintronic devices, and high-temperature superconductors. Direct epitaxial lift-off of the Cu film without etching gives a single-crystal-like Cu(111) foil. The Cu(111) foil exhibits a low resistivity of 3.75 x 10–8 Ω·m and good bending stability, showing only a 12% increase in resistance after 104 bending cycles. Cu(111) foils can be utilized as inexpensive, highly ordered, and conductive substrates for flexible electronics such as wearable solar cells, sensors, and flexible displays. Here, we show an example by electrodepositing epitaxial cuprous oxide on a Cu(111) foil

Epitaxial Electrodeposition of Cu(111) onto an l-Cysteine Self-Assembled Monolayer on Au(111) and Epitaxial Lift-Off of Single-Crystal-like Cu Foils for Flexible Electronics

Functional self-assembled monolayers (SAMs) of thiols on single-crystal metals provide two-dimensional (2D) soft templates for the highly ordered growth of crystalline materials. An epitaxial Cu(111) film is electrodeposited on a SAM of the amino acid l-cysteine on Au(111). Epitaxy is confirmed, with Cu(111) following the Au(111) in-plane and out-of-plane orientations with a small amount of twinned [511] orientation, which is shown by X-ray analysis. The mismatch between Cu(111) and the Au(111) substrate is −11.37%. This mismatch is lowered to −0.29% by forming a coincident site lattice in which nine unit meshes of Cu coincide with eight unit meshes of Au. Defect-mediated and coordination-controlled electrodeposition mechanisms are illustrated as two possible deposition mechanisms. The carboxylic (−COOH) and amine (−NH2) functional groups of the l-cysteine molecule are shown to be crucial for the epitaxy of Cu because a 1-butanethiol SAM on Au(111) which has no functional groups yields a textured film with no in-plane order. The (√3 × √3)R30° surface structure of l-cysteine SAM and the c(4 × 2) surface structure of 1-butanethiol SAM on Au(111) are discussed. A 3D model of the Cu lattice on the l-cysteine SAM on Au(111) is proposed. A possible coordination to Cu is shown, which facilitates the epitaxial nucleation and 2D growth of Cu. The Cu(111) films have potential as a substrate for catalysts for CO2 reduction, photovoltaic devices, spintronic devices, and high-temperature superconductors. Direct epitaxial lift-off of the Cu film without etching gives a single-crystal-like Cu(111) foil. The Cu(111) foil exhibits a low resistivity of 3.75 x 10–8 Ω·m and good bending stability, showing only a 12% increase in resistance after 104 bending cycles. Cu(111) foils can be utilized as inexpensive, highly ordered, and conductive substrates for flexible electronics such as wearable solar cells, sensors, and flexible displays. Here, we show an example by electrodepositing epitaxial cuprous oxide on a Cu(111) foil