Large-area Fabrication Research Articles

Engineering of antisolvent dripping for large-area perovskite solar cell fabrication under air ambient conditions

Engineering of antisolvent dripping for large-area perovskite solar cell fabrication under air ambient conditions

Large-Area Flexible Perovskite Light-Emitting Diodes Enabled by Inkjet Printing.

Metal halide perovskite light-emitting diodes (PeLEDs) are attracting increasing attention due to their potential applications in flat panel lighting and displays. The solution process, large-area fabrication, and flexibility are attractive properties of PeLEDs over traditional inorganic LEDs. However, it is still very challenging to deposit uniform perovskite films on flexible substrates using a blade or slot-die coating, as the flexible substrate is not perfectly flat. Here, the inkjet printing technique is adopted, and the key challenges are overcome step-by-step in preparing large-area films on flexible substrates. Double-hole transporting layers are first used and a wetting interfacial layer to improve the surface wettability so that the printed perovskite droplets can form a continuous wet film. The fluidic and evaporation dynamics of the perovskite wet layer is manipulated to suppress the coffee ring effect by solvent engineering. Uniform perovskite films are obtained finally on flexible substrates with different perovskite compositions. The peak external quantum efficiency of the inkjet-printed PeLEDs reaches 14.3%. Large-area flexible PeLEDs (4×7 cm2 ) also show very uniform emission. This work represents a significant step toward real applications of large-area PeLEDs in flexible flat-panel lighting.

Rapid Surface Reconstruction in Air-Processed Perovskite Solar Cells by Blade Coating.

Blade coating has been developed to be an essential technique for large-area fabrication of perovskite solar cells (PSCs). However, effective surface treatment of the perovskite layer, which is a critical step for improving PSC performance, remains challenges during blade coating due to the short interaction time between the modification solution and the perovskite layer, as well as the limited selection of available organic solvents. In this study, a novel modifier N,N-diphenylguanidine monohydrobromide (DPGABr) dissolved in acetonitrile (ACN) is blade coated on the MA0.7 FA0.3 PbI3 surface in air to reconstruct the perovskite surface in hundreds of milliseconds. This work finds that the solvent ACN rapidly dissolves organic iodide of the perovskite layer and leads to a PbI2 -rich surface, providing reactive sites for DPGABr to form a thin DPGABr/PbI2 complex layer. This surface reconstruction can effectively passivate defects and induce n-type doping on the perovskite surface to facilitate electron transfer. The resultant devices show a 15% improvement in average power conversion efficiency. More importantly, the devices with the surface reconstruction show outstanding long-term stability, with negligible performance degradation even after 1-year storage in air. This study presents a convenient and effective approach for improving the performance of blade-coated PSCs prepared in air.

Highly efficient nonlinear vortex beam generation by using a compact nonlinear fork grating

Vortex beams with an orbital angular momentum (OAM) are extremely important in optical trapping, optical micromachining, high-capacity optical communications, and quantum optics. Nonlinear generation of such a vortex beam enables vortex beams to be obtained at new wavelengths, which opens up new possibilities for all-optical switching and manipulation of vortex beams. However, previous nonlinear vortex beam generation suffers from either low efficiency or low-level integration. Here, we use the technique of ultraviolet photolithography-assisted inductively coupled plasma (ICP) etching to realize a compact nonlinear fork grating for high-efficiency nonlinear vortex beam generation. In our experiment, the depth of such a compact nonlinear fork-grating structure can be precisely controlled by etching time. The vortex beams with a topological charge of l = ±1, ± 2, ± 3 can be generated in the far field, and the normalized nonlinear conversion efficiency of such nonlinear vortex beam is 189% W−1cm−2. Our method not only provides an efficient and compact method for nonlinear vortex beam manipulation but also suits for timesaving and large-area nonlinear functional device fabrication.

Shape tuning of large area silicon nanotip arrays through reactive ion etching

Nanostructures formed in silicon form an important class of structures that span a broad spectrum of application areas. Of these, columnar structures of silicon featuring tiplike apexes have their own niche applications. The ability to afford shape tunability for these structures further enhances their application potential. In this paper, we present our findings on the large area fabrication of silicon nanotips defined through microsphere lithography and shape tuned through a combination of different reactive ion etching (RIE) techniques. The self-sharpening mechanism of the tips when using nonplanar etch masks (microspheres) under anisotropic etching conditions is elucidated. We further show that depending on the manner of etching (continuous versus discrete multistep etch), identical anisotropic etching recipes produce vastly different tip morphologies. Hourglass-shaped silicon tips were obtained when silicon was subjected to anisotropic followed by isotropic etching conditions. Sharp silicon tips with tip apex radii on the order of 2 nm have been successfully realized when the RIE shape tuned tips were subjected to a series of oxidative sharpening steps.

Enhanced optical sensing with metal-insulator-metal nanohole arrays integrated with silver nanoparticles

The field of plasmonic sensing has witnessed rapid advancements in recent years. This work proposes an innovative methodology that employs metal–insulator-metal (MIM) nanohole arrays integrated with ring-shaped silver nanoparticles (AgNPs) to serve as an effective plasmonic refractive index sensor. The hybrid substrates are prepared using a combination of nanosphere lithography (NSL), reactive ion etching, and an enhanced plasmonic site-selective photocatalytic reaction, ensuring large-area fabrication, high throughput, and cost-effectiveness. The resonance peaks observed in the visible-NIR spectra are attributed to the coupling of surface plasmon resonance modes between MIM structures and AgNPs. The resonance wavelength exhibits sensitively to changes in the surrounding medium within the refractive index range of 1 to 1.5, with a remarkable sensitivity of 835 nm/RIU. Our findings reveal the significant potential of this technology for advancing optical sensing applications.

Fabrication of Large-Area Fully Alloyed Ag/Au Nanoparticle Arrays

Fabrication of Large-Area Fully Alloyed Ag/Au Nanoparticle Arrays

Hierarchically manufactured chiral plasmonic nanostructures with gigantic chirality for polarized emission and information encryption

Chiral metamaterials have received significant attention due to their strong chiroptical interactions with electromagnetic waves of incident light. However, the fabrication of large-area, hierarchically manufactured chiral plasmonic structures with high dissymmetry factors (g-factors) over a wide spectral range remains the key barrier to practical applications. Here we report a facile yet efficient method to fabricate hierarchical chiral nanostructures over a large area (>11.7 × 11.7 cm2) and with high g-factors (up to 0.07 in the visible region) by imparting extrinsic chirality to nanostructured polymer substrates through the simple exertion of mechanical force. We also demonstrate the application of our approach in the polarized emission of quantum dots and information encryption, including chiral quick response codes and anti-counterfeiting. This study thus paves the way for the rational design and fabrication of large-area chiral nanostructures and for their application in quantum communications and security-enhanced optical communications.

Toward an understanding of the mechanism of mixed-salt-mediated CVD growth of MoSe2

The use of liquid precursors in chemical vapor deposition (CVD) techniques is advantageous for growing large-area, uniform two-dimensional (2D) transition-metal dichalcogenides (TMDs) compared to conventional methods using solid precursors. While various liquid precursors have been explored, recent studies highlight the use of mixed-salt precursors for growing uniform and wafer-scale TMDs. In this study, we propose a growth mechanism and present our findings on the epitaxial growth of MoSe2 domains as a function of annealing/growth time and H2 flow rate using Na2MoO4 and Na2SeO3 mixed-salt precursors. We confirm that the increase in the annealing time enhances the distribution of spin-coated precursors, leading to a rise in flake number density. On the other hand, prolonged growth time results in better-aligned MoSe2 flakes along the c-sapphire substrate step-edges. A significant finding is the dynamic diffusion of dendritic structures within large domains over the growth period, owing to the constant dissolution and recrystallization in the presence of residual liquid alloys. An increase in the H2 flow during CVD growth yields small, triangular domains aligned with the step edges, a result of the efficient reduction of precursor alloys and subsequent selenization. Our results provide an insight on achieving uniform and aligned morphology in CVD growth of 2D TMDs using liquid-phase precursors, a crucial step toward large-area fabrication.

Artificial Visual Synaptic Architecture with High-Linearity Light-Modulated Weight for Optoelectronic Neuromorphic Computing.

A brain-like neuromorphic computing system, as compared with traditional Von Neumann architecture, has broad application prospects in the fields of emerging artificial intelligence (AI) due to its high fault tolerance, excellent plasticity, and parallel computing capability. A neuromorphic visuosensory and memory system, an important branch of neuromorphic computing, is the basis for AI to perceive, process, and memorize optical information, now still suffering from nonlinearity of synaptic weight, crosstalk issues, and integration incompatibility, hindering the high-level training and inference accuracy. In this work, we propose a new optoelectronic neuromorphic architecture by integrating an electrochromic device and a perovskite photodetector. Ascribing to the superior memory characteristics of the electrochromic device and sensitive light response of the perovskite photodetector, the neuromorphic device shows typical visual synaptic functionalities such as light triggering, neural facilitation, long-term potentiation, and depression (LTP and LTD). Furthermore, by adjusting the intensity and wavelength of external light signals, the visual synaptic function of the device can be modulated, enabling the device to exhibit high weight linearity in all current output ranges and improve information processing capability and image recognition accuracy. Moreover, both the electrochromic and perovskite layers possess the advantage of large area fabrication and integration, which enables the fabrication of large device arrays with high integration compatibility and scalability. In this study, 10 × 10 device arrays are demonstrated and each device shows uniform light responses, memory behaviors, and synaptic performances. MNIST and CIFAR-10 algorithms are used to simulate the image recognition properties of the synaptic architecture, and the calculated recognition accuracy is 97.94 and 91.04%, respectively, with an error less than 2.5%. The proposed artificial visual neuromorphic architecture will provide a potential device prototype for efficient visual neuromorphic systems.

Nanoparticles of poly(3-hexylthiophene): Toward a solvent-independent performance of electrochromic films

Nanoparticles of poly(3-hexylthiophene), P3HT(NP), uniquely enable the preparation of stable dispersions in environmentally-friendly media and thus offer a sustainable liquid phase fabrication of electrochromic device structures. In this work, we assess the electrochromic performance of P3HT(NP) films spray-coated from either tetrahydrofuran (THF)-water or chloroform (CHCl3)-ethanol dispersions on ITO substrates. The nanoparticle films exhibit consistent and reproducible high optical contrast values of around 50 %, t90-switching speeds of about 0.45 s and a cycling stability of approximately 200 cycles for a 20 % performance retention, independent of the solvent being used. Conversely, non-nanostructured P3HT films spray-coated from THF or CHCl3 reveal a strong solvent dependent variability in their electrochromic behavior presenting low optical contrast, high switching speeds and fast degradation rates in the case of CHCl3. The solvent independent electrochromic characteristics of P3HT nanoparticle films is related to a consistent availability of accessible electroactive sites provided by a homogeneous porous P3HT network structure formed on the underlying substrate, as probed by SEM and profilometric studies. Our findings reveal that the use of nanoparticles of P3HT and its environmentally benign liquid phase processing, a concept which is extendable to other electrochromic polymers, opens a sustainable pathway toward the large-area fabrication of electrochromic device structures with favorable and consistent performance parameters.

Facile Fabrication and Characterization of Oriented and Multilayer Thin Films of Solution Processable Conjugated Polymer

Fabrication of multilayer thin films of solution‐processable organic semiconductors has great potential in organic electronics, but adopting existing thin‐film techniques to attain this is highly cumbersome. Herein, a unique unidirectional floating film transfer method has been utilized, which allows the facile fabrication of large area and oriented thin films of conjugated polymers. This method has successfully fabricated and characterized multilayer and oriented thin films of regioregular poly(3‐hexylthiophene) without having any adverse effect on the underlying layers. Optical characterizations reveal that fabricated thin films are anisotropic with a dichroic ratio of 2.2 having a single layer thickness of 14.5 nm. X‐ray diffraction results demonstrate uniformity in the crystallinity of the multilayered thin film with comparable crystallite size and interplanar spacing with purely edge‐on molecular orientation. The organic field effect transistor fabricates using multilayer thin films and also exhibits a uniform and saturated charge carrier mobility of about 0.1 cm2 V−1 s−1.

Quasi-Random Multimetallic Nanoparticle Arrays.

This paper describes a nanofabrication procedure that can generate multiscale substrates with quasi-random microregions of nanoparticle arrays having different periodicities and metals. We combine cycles of large-area nanoparticle array fabrication with solvent-assisted wrinkle lithography to mask and etch quasi-random areas of prefabricated nanoparticles to control the fill factors of the arrays. The approach is highly flexible, and parameters, including nanoparticle size and material, array geometry, and fill factor, can be tailored independently. Multimetallic nanoparticle arrays can support surface lattice resonances at fill factors as low as 20% and can function as nanoscale cavities for lasing action with as few as 10% of the nanoparticles in an array. We demonstrated that multimetallic nanoparticle substrates that combine two or three arrays with different periodicities can exhibit lasing responses over visible and near-infrared wavelengths. Our work showcases the robust optical responses of multimetallic and periodic devices for broadband light manipulation.

Using image analysis techniques to enhance TFT-LCD manufacturing yield through timely detection of PI alignment layer defects

This study aims to develop a solution to the manufacturing process defects of thin-film transistor liquid crystal display (TFT-LCD) panels. Specifically, it focuses on online image analysis for detecting uneven coatings of the polyimide (PI) alignment layers, which are crucial in the TFT-LCD manufacturing process. The PI solution is typically applied to a substrate surface using an array of nozzles via droplet deposition. During this process, nozzle clogging can cause a series of defects in the form of spots on the alignment layer. These defects impact the alignment of liquid crystal molecules in the TFT-LCD, leading to decreased display quality, reduced visibility, uneven brightness, and compromised image details. If suspected signs of alignment layer spots are identified, the image analysis technology assists online inspectors with prompt responses to minimize TFT-LCD production errors. The results of this study demonstrate timely detection of alignment layer spots, prevention of their progression, and significant reduction of the time required for manual inspection to improve manufacturing yield. This newly developed approach is applicable to not only TFT-LCD production monitoring but also smart display panel manufacturing, thereby providing significant value in high-volume and large-area panel fabrication processes.

Green Solvent Processable, Asymmetric Dopant-Free Hole TransportLayer Materialfor Efficient and Stable n-i-p Perovskite Solar Cells and Modules.

The use of dopant-free hole transport layers (HTLs) is critical in stabilizing n-i-p perovskite solar cells (pero-SCs). However, these HTL materials are often processed with toxic solvents, which is not ideal for industrial production. Upon substituting them with green solvents, a trade-off emerges between maintaining the high crystallinity of the HTL materials and ensuring high solubility in the new solvents. In this paper, we designed a novel, linear, organic small molecule, BDT-C8-3O, by introducing an asymmetric polar oligo(ethylene glycol) side chain. This method not only overcomes the solubility limitations in green solvents but also enables stacking the conjugated main chains in two patterns, which further enhances crystallinity and hole mobility. As a result, the n-i-p pero-SCs based on chlorobenzene- or green (natural compound) solvent 3-methylcyclohexanone-processed BDT-C8-3O HTL that without any dopant delivered world-recorded PCEs of 24.11% (certified of 23.82%) and 23.53%, respectively. The devices also demonstrated remarkable operational and high-temperature stabilities, maintaining over 84% and 79.5% of their initial efficiency for 2000 h, respectively. Encouragingly, dopant-free BDT-C8-3O HTL exhibits significant advantages in large-area fabrication, achieving state-of-the-art PCEs exceeding 20% for 5×5 cm2 modules (active area: 15.64 cm2), even when processed using green solvents.

Concretized structural evolution supported assembly-controlled film-forming kinetics in slot-die coated organic photovoltaics

Bulk-heterojunction structured small-area organic solar cells are approaching 20% power conversion efficiency, but the blurred film-forming kinetics in the fabrication of large-area devices causes significant PCE loss and restrains the potential of commercialization. Such blurring came from insufficient knowledge of structural evolution during the film-forming process. Here, we concretize the evolution process with structures detailed to the submolecular level by comprehensive investigations of in-situ UV-vis spectroscopy, Atomic Force Microscope, Grazing Incident Wide Angle X-ray Scattering, and molecular dynamic simulation. With such hierarchical structural knowledge, assembly-controlled film-forming kinetics is proposed to explain the whole picture. Such assembly is determined by molecule configuration and can be tuned via external conditions. Understanding this kinetics will contribute to screening large-area device fabrication conditions, and the detailed structural knowledge could inspire the future design of novel photovoltaic materials that are intrinsically excellent in large-area device fabrications.

Thin Film Transistors Incorporating Ultrapure Semiconducting Single-Walled Carbon Nanotubes and Green Dielectrics

Printed electronics is a burgeoning field that has received intense research interest and is beginning to experience commercial successes. Single-walled carbon nanotubes (SWNTs) are a unique and promising building block for incorporation into next generation superfast electronic devices. SWNTs have very high carrier mobilites, with band gaps compatible for integration into logic circuits. Their excellent mechanical flexibility allows for potential incorporation into flexible printed electronics, enabling fully-printed transistors and circuits with performances that support low cost, large area fabrication. Progress in incorporating SWNTs into commercial devices has been hindered by the presence of metallic SWNTs, which are produced alongside semiconducting SWNTs during synthesis, and negatively impact device performance. Fabrication of ambipolar SWNT organic thin film transistors (OTFTs) with high carrier mobilities and high on/off ratios remains particularly challenging; many examples in the literature required high temperature, expensive and energy-demanding processes.Since the initial discovery of conjugated polymer-assisted dispersion and purification of SWNTs in 2008, several polymer families have been successfully shown to selectively disperse semiconducting SWNTs. However, only a relatively small number of these supramolecular complexes have been incorporated into OTFTs. We used a novel conjugated polymer to exclusively disperse semiconducting SWNTs. The dispersal procedure requires a simple sonication and centrifugation, during which the metallic SWNTs sediment out. Solution purity was evaluated using UVVis- NIR and Raman spectroscopies. The resulting dispersions are amenable to solution processing techniques such drop casting and spin coating, allowing for the potential for large area device fabrication at room temperature. Ambipolar OTFTs were fabricated under ambient conditions using this solution and tested in both air and under inert atmosphere. The presence of excess conjugated polymer, solution deposition techniques, SWNT density, surface treatment, and post-fabrication treatment were all investigated to determine which parameters facilitated the production of OTFTs with high mobilities (>20 cm2V-1s-1), high on/off ratios (10^6-10^8), negligeble hysteresis, controlled threshold voltages, and high bias stability.[1] Protocols for sorting and dispersing ultrapure sc-SWNTs with conjugated polymers for thin-film transistor (TFT) applications have been well refined. Conventional wisdom dictates that removal of excess unbound polymer through filtration or centrifugation is necessary to produce high- erformance TFTs. However, this is time-consuming, wasteful, and resource-intensive. We challenge this paradigm and demonstrate that excess unbound polymer during semiconductor film fabrication is not necessarily detrimental to device performance.[2] With focus on further improving device performance, we look to green, compostable dielectrics to pair with SWCNTs. We report a tri-layer dielectric using poly (lactic acid) (PLA), poly(vinyl alcohol)/cellulose nanocrystals (PVAc) and toluene diisocyanate terminated poly(caprolactone) (TPCL) which we integrated into SWCNT based TFTs in a top gate bottom contact architecture. The PVA provides a high dielectric constant due to the hydroxy groups, the cellulose is used to optimize the viscosity, the TPCL layer provides a robust hydrophobic surface[3], and the PLA eliminates the interfacial charge traps present in the PVAc. This leads to a decrease in leakage currents and reduced the polarity at the dielectric/semiconductor interface. The TFTs fabricated using tri-layer dielectrics led to air stable and balanced hole and electron mobilities which was not observed for the PVAc/TPCL bilayer systems with supressed hole mobility. These TFTs were then used to study the impact of electrochemical doping on the performance of sc-SWCNT TFTs when switching from n-type, where an electrical double layer is formed, to p-type, where the TFSI anions are free to interact with the sc-SWCNTs.[4]The following presentation will focus on the engineering of sc-SWNTs based electronic devices. The choice of conjugated wrapping polymer, dielectric and processing conditions on film formation and the TFT device performance.

Rapid, Large Area Fabrication of Porous Graphene Networks Using Photothermal Flash Lamp Carbonization for High Performance Supercapacitors

Graphene materials exhibit intriguing physical, chemical, and mechanical properties. Remarkably high surface area and electrical conductivity make them excellent materials for energy storage applications, especially supercapacitors. The production of graphene requires relatively long processing times, extremely high temperatures within controlled atmospheres, and/or involves multi-step reactions that present challenges for high-throughput fabrication of energy storage devices. Moreover, supercapacitor devices fabricated using graphene suffer from low areal capacitance mainly due to the tortuous path of electrolytes in accessing the bulk of the material, which limits charge storage and transport throughout the thickness of the device.We have developed an efficient photothermal route to large-scale production of few-layer graphene within milliseconds from polymers using high intensity xenon flash lamp on carbon fiber at ambient conditions. The xenon flash lamp provides large-area illumination and a wide emission band (300 nm –1100 nm) that was used to convert the polymeric material directly into few-layer graphene upon millisecond exposures. Specifically, photothermally heating of polyaniline, a rod like polymer with a large absorption cross-section in the emission spectra of xenon flash lamp, led to the formation of macroporous network as shown in Figure 1a. Characterization revealed the formation of few layer graphene ( ID/IG ratio less than 0.3) with good adhesion to the carbon fiber support, enabling the formation of devices in-situ. We investigated the influence of morphology as well as graphene quality on the energy storage capabilities of the obtained devices as shown in Figure 1b. The supercapacitor devices prepared with macroporous few-layer graphene network exhibited a superior areal capacitance of 200 mF/cm2 at 10 mV/s which is an order of magnitude higher than few layer graphene with a conventional film like structure. Also, it retained more than 70% of its capacitance even after increasing the scan rate to 100 mV/s. Moreover, large area processability enabled by this photothermal approach allowed us to easily produce graphene-derived high-performance supercapacitor devices over areas greater than 100 cm2 (Figure 1c) within a few milliseconds at ambient conditions. Hence, this work provides an energy efficient and scalable route to produce high-quality few layer graphene devices with superior energy storage capabilities. Figure 1

(Invited) Development of Non-Fused Nonfullerene Acceptors Bearing Spiro-Substituted Structures and Application to Green-Light Wavelength-Selective Organic Solar Cells

Organic solar cells (OSCs) have been extensively investigated as next-generation energy sources due to their potential for large-area fabrication, light weight, flexibility. The active layer of OSCs is composed of a blend of donors and acceptors, which form bulk heterojunction structures in the films. The development of A-D-A-type nonfullerene acceptors (NFAs) with large fused-ring donor structures have significantly accelerated OSC research. On the other hand, non-fused electron-accepting p-conjugated compounds have been investigated recently for application to NFAs. In this presentation, we focus on cyclopentene-annelated thiophene with spiro-substituted 2,7-bis(2-ethylhexyl)fluorene (FT) as a rigid and sterically bulky linker unit and develop a non-fused NFA containing FT units. We also focus on the development spiro-substituted NFAs with green-light wavelength-selective absorbance. The combination of these acceptors and poly(3-hexylthiophene) can produce green-light wavelength-selective OSCs for application in new greenhouse agrivoltaics.

Optical Characterisation of Plasmonic Indium Lattices Fabricated Via Electrochemical Deposition

Indium is an emerging plasmonic material that offers to extend the plasmonic applications given by gold and silver from the visible to the ultraviolet spectral range, with applications in imaging, sensing, and lasing. However, due to the high-vapor pressure/low melting temperature of indium, nanofabrication of pre-defined metallic indium nanostructures is non-trivial.In this work, we show the potential of selective area electrochemical deposition for the manufacturing of large-area arrays of indium pillars, which can be used for plasmonic applications. We combine electrochemical deposition with substrate-conformal imprint lithography to realize these large-scale indium nanoparticle arrays, having well-defined dimensions. This template growth results into well-defined hexagonal array of pillars with a mean height of 235 nm having a standard deviation of 60 nm.To highlight the potential of this electrochemical-based technique for plasmonic applications, we have performed angle-dependent extinction measurements using s-polarized light and using a RI matching oil. We found that these indium nanopillar arrays exhibit a strong plasmonic response due to the coupling to the plasmonic surface lattice resonances (SLRs). Furthermore, we have simulated the optical response of this indium nanopillar array using finite difference time domain (FDTD) simulations. In these simulations, we included the morphology obtained from SEM and the electrical permittivity of elemental indium. We found that the simulated extinction spectra agree well with the experimentally obtained spectra at 0˚ and 8˚ incidence, despite the polydispersity of the indium pillar height and defects in the hexagonal array.Our results therefore demonstrate the possibility of realizing large-area fabrication of indium plasmonic nanoparticles, which can be used for plasmonic applications. Given the low-cost and scalable nature of this technique, this work opens new possibilities in the design and fabrication of large-area plasmonic metasurfaces that operate in the UV spectral range. Future extensions of this work may leverage the indium mask-constrained growth to tailor even further the shape of the nanoparticle and hence give a powerful tuning knob to tailor plasmonic resonances.