Abstract:Thin film transistors (TFTs) are key components for the fabrication of electronic and optoelectronic devices, resulting in a push for the wider exploration of semiconducting materials and cost‐effective synthesis processes. In this report, a simple approach is proposed to achieve 2‐nm‐thick indium oxide nanosheets from liquid metal surfaces by employing a squeeze printing technique and thermal annealing at 250 °C in air. The resulting materials exhibit a high degree of transparency (>99 %) and an excellent … Show more
“…Hence, this study provides a pathway to utilize ultrathin In 2 O 3 layers as visible-active artificial optoelectronic synapses, which can find applications in next-generation bionic eyes and intelligent display systems. 28 ■ RESULTS AND DISCUSSION Atomically thin In 2 O 3 sheets are prepared using the LM synthesis technique followed by annealing (Figure 1a), to improve disorder at the grain boundaries of the material alongside increasing the grain size for improved mobility and photodetection properties 25 (see the Experimental Section for further details). Figure 1b shows the AFM characterization of a eV and the presence of oxygen peaks at 529.9 eV, which is in accordance with that of c-In 2 O 3 reported in the literature.…”
Section: ■ Introductionmentioning
confidence: 99%
“…25 With increasing grain sizes due to annealing, there is a reduction in the intergranular distorted region in the polycrystalline sheet, resulting in improved mobility due to fewer barriers. 25 This increased mobility also results in increased carrier diffusion length, which improves the charge carrier extraction within the system, resulting in increased photocurrent in the annealed samples in comparison to the pristine ones. 25 Furthermore, it has also been demonstrated previously that despite the generation of photocurrent in In 2 O 3 due to existence of V o , the presence of more than required V o in In 2 O 3 acts as recombination centers passivating photocurrent generation.…”
Section: ■ Introductionmentioning
confidence: 99%
“…25 This increased mobility also results in increased carrier diffusion length, which improves the charge carrier extraction within the system, resulting in increased photocurrent in the annealed samples in comparison to the pristine ones. 25 Furthermore, it has also been demonstrated previously that despite the generation of photocurrent in In 2 O 3 due to existence of V o , the presence of more than required V o in In 2 O 3 acts as recombination centers passivating photocurrent generation. 23 Such an excess number of V o can be passivated through annealing, which improves the overall photocurrent generation in In 2 O 3 and response to visible light.…”
Section: ■ Introductionmentioning
confidence: 99%
“…The high-resolution TEM image of a polycrystalline grain indicates a d-plane spacing of 0.3 nm, which is associated with the (222) plane of cubic In 2 O 3 25. The ring-like selected area electron diffraction (SAED) patterns (as seen in Figure1d) further affirm the polycrystalline nature of the In 2 O 3 nanosheets, which can be associated with minimized anisotropic carrier mobilities along the material's crystal axis 25. The low-resolution TEM image and AFM and optical images of the nanosheet are shown in Supporting Information Section 1Figure S1.…”
One of the key requirements to emulate synaptic features in optoelectronic devices is the presence of persistent photoconductivity (PPC). While there are several visible-active materials, transparent semiconducting oxides (TSOs) have commercially established production processes and applications. Despite the inherently exceptional optoelectronic properties in many atomically thin TSOs along with PPC, their wide band gap renders them feasible only for ultraviolet (UV)-active synaptic applications. Hence, approaches need to be developed that allow one to tailor such semiconductors for visible-active optoelectronic synapses that are a strong emerging area of research. Over the past few years, liquid metal (LM) printing techniques have enabled the realization of many nonstratified oxides in an atomically thin form, resulting in oxide systems with enhanced optoelectronic performances, which can be further engineered using postsynthesis processing techniques. Here, we utilize a nonlayered ultrathin oxide, indium oxide (In 2 O 3 ), engineered to demonstrate a photoelectrical response in the visible spectrum with a peak responsivity of 6.67 × 10 3 A/W at 455 nm. The 2.2 nm thin sheets operating under a driving voltage of 200 mV are successfully able to detect short pulses under 500 ms while showcasing PPC characteristics without additional bias. Key synaptic and multisynaptic functionalities are replicated using blue and green light sources, demonstrating a viable pathway to integrate atomically thin oxide semiconductors for visible light-active optoelectronic synaptic applications.
“…Hence, this study provides a pathway to utilize ultrathin In 2 O 3 layers as visible-active artificial optoelectronic synapses, which can find applications in next-generation bionic eyes and intelligent display systems. 28 ■ RESULTS AND DISCUSSION Atomically thin In 2 O 3 sheets are prepared using the LM synthesis technique followed by annealing (Figure 1a), to improve disorder at the grain boundaries of the material alongside increasing the grain size for improved mobility and photodetection properties 25 (see the Experimental Section for further details). Figure 1b shows the AFM characterization of a eV and the presence of oxygen peaks at 529.9 eV, which is in accordance with that of c-In 2 O 3 reported in the literature.…”
Section: ■ Introductionmentioning
confidence: 99%
“…25 With increasing grain sizes due to annealing, there is a reduction in the intergranular distorted region in the polycrystalline sheet, resulting in improved mobility due to fewer barriers. 25 This increased mobility also results in increased carrier diffusion length, which improves the charge carrier extraction within the system, resulting in increased photocurrent in the annealed samples in comparison to the pristine ones. 25 Furthermore, it has also been demonstrated previously that despite the generation of photocurrent in In 2 O 3 due to existence of V o , the presence of more than required V o in In 2 O 3 acts as recombination centers passivating photocurrent generation.…”
Section: ■ Introductionmentioning
confidence: 99%
“…25 This increased mobility also results in increased carrier diffusion length, which improves the charge carrier extraction within the system, resulting in increased photocurrent in the annealed samples in comparison to the pristine ones. 25 Furthermore, it has also been demonstrated previously that despite the generation of photocurrent in In 2 O 3 due to existence of V o , the presence of more than required V o in In 2 O 3 acts as recombination centers passivating photocurrent generation. 23 Such an excess number of V o can be passivated through annealing, which improves the overall photocurrent generation in In 2 O 3 and response to visible light.…”
Section: ■ Introductionmentioning
confidence: 99%
“…The high-resolution TEM image of a polycrystalline grain indicates a d-plane spacing of 0.3 nm, which is associated with the (222) plane of cubic In 2 O 3 25. The ring-like selected area electron diffraction (SAED) patterns (as seen in Figure1d) further affirm the polycrystalline nature of the In 2 O 3 nanosheets, which can be associated with minimized anisotropic carrier mobilities along the material's crystal axis 25. The low-resolution TEM image and AFM and optical images of the nanosheet are shown in Supporting Information Section 1Figure S1.…”
One of the key requirements to emulate synaptic features in optoelectronic devices is the presence of persistent photoconductivity (PPC). While there are several visible-active materials, transparent semiconducting oxides (TSOs) have commercially established production processes and applications. Despite the inherently exceptional optoelectronic properties in many atomically thin TSOs along with PPC, their wide band gap renders them feasible only for ultraviolet (UV)-active synaptic applications. Hence, approaches need to be developed that allow one to tailor such semiconductors for visible-active optoelectronic synapses that are a strong emerging area of research. Over the past few years, liquid metal (LM) printing techniques have enabled the realization of many nonstratified oxides in an atomically thin form, resulting in oxide systems with enhanced optoelectronic performances, which can be further engineered using postsynthesis processing techniques. Here, we utilize a nonlayered ultrathin oxide, indium oxide (In 2 O 3 ), engineered to demonstrate a photoelectrical response in the visible spectrum with a peak responsivity of 6.67 × 10 3 A/W at 455 nm. The 2.2 nm thin sheets operating under a driving voltage of 200 mV are successfully able to detect short pulses under 500 ms while showcasing PPC characteristics without additional bias. Key synaptic and multisynaptic functionalities are replicated using blue and green light sources, demonstrating a viable pathway to integrate atomically thin oxide semiconductors for visible light-active optoelectronic synaptic applications.
“…These properties make gallium-based alloys particularly suitable for a wide range of applications in flexible electronics and soft robotics alongside chemical and electrochemical processes. − In the context of electrochemistry, one of the most intriguing merits of liquid metals is the dynamic liquid–liquid interface that is established when they are in contact with an immiscible electrolyte . The liquid metal–electrolyte interface offers an atomically smooth yet electrochemically active template for growing or depositing a range of precursors into thin layers, , which presents great tunability for synthesizing materials in the nanoscale. , …”
Liquid metal−electrolyte can offer electrochemically reducing interfaces for the self-deposition of low-dimensional nanomaterials. We show that implementing such interfaces from multiprecursors is a promising pathway for achieving nanostructured films with combinatory properties and functionalities. Here, we explored the liquid metal-driven interfacial growth of metal tellurides using eutectic gallium−indium (EGaIn) as the liquid metal and the cation pairs Ag + -HTeO 2 + and Cu 2+ -HTeO 2 + as the precursors. At the EGaIn− electrolyte interface, the precursors were reduced and self-deposited autogenously to form interconnected nanoparticle networks. The deposited materials consisted of metal telluride and tellurium with their relative abundance depending on the metal ion type (Ag + and Cu 2+ ) and the metal-to-tellurium ion ratios. When used as electrode modifiers, the synthesized materials increased the electroactive surface area of unmodified electrodes by over 10 times and demonstrated remarkable activity for model electrochemical reactions, including HexRu(III) responses and dopamine sensing. Our work reveals the promising potential of the liquid metal-templated deposition method for synthesizing complex material systems for electrochemical applications.
Abstract2D metal oxides (2DMOs) have recently emerged as a high‐performance class of ultrathin, wide bandgap materials offering exceptional electrical and optical properties for a wide area of device applications in energy, sensing, and display technologies. Liquid metal printing represents a thermodynamically advantageous strategy for synthesizing 2DMOs by a solvent‐free and vacuum‐free scalable method. Here, recent progress in the field of liquid metal printed 2D oxides is reviewed, considering how the physics of Cabrera‐Mott oxidation gives this rapid, low‐temperature process advantages over alternatives such as sol‐gel and nanoparticle processing. The growth, composition, and crystallinity of a burgeoning set of 1–3 nm thick liquid metal printed semiconducting, conducting, and dielectric oxides are analyzed that are uniquely suited for the fabrication of high‐performance flexible electronics. The advantages and limitations of these strategies are considered, highlighting opportunities to amplify the impact of 2DMO through large‐area printing, the design of doped metal alloys, stacking of 2DMO to electrostatically engineer new oxide heterostructures, and implementation of 2D oxide devices for gas sensing, photodetection, and neuromorphic computing.
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