Plasmonic nanoparticle enhanced and extended performance of Light-sensitive nanocrystal skins

ABSTRACTWe report on light-sensitive nanocrystal skin (LS-NS) platforms composed of monolayer visible nanocrystals (NCs) on top of bilayers of polyelectrolyte polymers. These LS-NS devices are operated on the principle of photogenerated potential buildup, unlike common photodetectors that operate on the basis of charge collection. The resulting devices are as highly sensitive as common photosensors, despite utilizing a monolayer of NCs and requiring no applied external bias. In this device architecture, using only a single NC monolayer also allows to reduce noise current generation. This LS-NS platform is highly stable under ambient conditions with fully sealed NC monolayer, promising for low-cost large-area UV/visible sensing applications. However, such visible NC based LS-NS devices exhibit limited performance in the long wavelength range due to the low optical absorption of these NCs (e.g., CdTe NCs) in this spectral range. Here, to enhance the device sensitivity, incorporating silver nanoparticles into LS-NS is proposed and demonstrated. For that, the optical absorption of CdTe monolayer NCs in the LS-NS devices is increased using the embedded silver nanostructures. With plasmon coupling, we observe a 2.6-fold enhancement factor in the photosensitivity around the localized surface plasmonic resonance peak of the nanostructures. Higher sensitivity improvement is also obtained at longer wavelengths. To predict the enhancement in the sensitivity of the LS-NS, numerical simulations are performed and the simulation results are found to agree well with the experimental data. Plasmonically enhanced LS-NS hold great promise for large-area photosensing applications extending from UV to IR including windows and facades of smart buildings.

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Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020190250 ◽

2020 ◽

Vol 90 (3) ◽

pp. 30502

Author(s):

Alessandro Fantoni ◽

João Costa ◽

Paulo Lourenço ◽

Manuela Vieira

Keyword(s):

Amorphous Silicon ◽

High Throughput Screening ◽

Simulation Analysis ◽

Low Cost ◽

Deposition Process ◽

Large Area ◽

Sidewall Roughness ◽

Sensing Applications ◽

Fabrication Defects ◽

The Impact

Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.

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Low cost sponge based piezocapacitive sensors using a single step leavening agent mediated autolysis process

Journal of Materials Chemistry C ◽

10.1039/c8tc00972d ◽

2018 ◽

Vol 6 (20) ◽

pp. 5473-5481 ◽

Cited By ~ 7

Author(s):

Chithra Parameswaran ◽

Dipti Gupta

Keyword(s):

Real Time ◽

Low Cost ◽

Single Step ◽

Large Area ◽

Sensing Applications ◽

Autolysis Process

A single step, low cost, large area and shape scalable method of obtaining elastomer sponge is achieved through leavening agent autolysis with exceptional sensitivity tunability for real time sensing applications.

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Laser printed two-dimensional transition metal dichalcogenides

Scientific Reports ◽

10.1038/s41598-021-81829-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Omar Adnan Abbas ◽

Adam Henry Lewis ◽

Nikolaos Aspiotis ◽

Chung-Che Huang ◽

Ioannis Zeimpekis ◽

...

Keyword(s):

Transition Metal ◽

Low Cost ◽

Transition Metal Dichalcogenides ◽

Light Modulation ◽

Ambient Conditions ◽

Large Area ◽

Laser Printing ◽

Metal Dichalcogenides ◽

Versatile Technique ◽

Post Synthesis

AbstractLaser processing is a highly versatile technique for the post-synthesis treatment and modification of transition metal dichalcogenides (TMDCs). However, to date, TMDCs synthesis typically relies on large area CVD growth and lithographic post-processing for nanodevice fabrication, thus relying heavily on complex, capital intensive, vacuum-based processing environments and fabrication tools. This inflexibility necessarily restricts the development of facile, fast, very low-cost synthesis protocols. Here we show that direct, spatially selective synthesis of 2D-TMDCs devices that exhibit excellent electrical, Raman and photoluminescence properties can be realized using laser printing under ambient conditions with minimal lithographic or thermal overheads. Our simple, elegant process can be scaled via conventional laser printing approaches including spatial light modulation and digital light engines to enable mass production protocols such as roll-to-roll processing.

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Low-Cost, Disposable, Flexible and Highly Reproducible Screen Printed SERS Substrates for the Detection of Various Chemicals

Scientific Reports ◽

10.1038/srep10208 ◽

2015 ◽

Vol 5 (1) ◽

Cited By ~ 74

Author(s):

Wei Wu ◽

Li Liu ◽

Zhigao Dai ◽

Juhua Liu ◽

Shuanglei Yang ◽

...

Keyword(s):

Screen Printing ◽

Large Scale ◽

Low Cost ◽

Large Area ◽

Sers Substrates ◽

Sensing Applications ◽

Relative Standard ◽

Sers Detection ◽

On Line ◽

Liquid Milk

Abstract Ideal SERS substrates for sensing applications should exhibit strong signal enhancement, generate a reproducible and uniform response and should be able to fabricate in large-scale and low-cost. Herein, we demonstrate low-cost, highly sensitive, disposable and reproducible SERS substrates by means of screen printing Ag nanoparticles (NPs) on a plastic PET (Polyethylene terephthalate) substrates. While there are many complex methods for the fabrication of SERS substrates, screen printing is suitable for large-area fabrication and overcomes the uneven radial distribution. Using as-printed Ag substrates as the SERS platform, detection of various commonly known chemicals have been done. The SERS detection limit of Rhodamine 6G (R6G) is higher than the concentration of 1 × 10−10 M. The relative standard deviation (RSD) value for 784 points on the detection of R6G and Malachite green (MG) is less than 20% revealing a homogeneous SERS distribution and high reproducibility. Moreover, melamine (MA) is detected in fresh liquid-milk without additional pretreatment, which may accelerate the application of rapid on-line detection of MA in liquid milk. Our screen printing method highlights the use of large-scale printing strategies for the fabrication of well-defined functional nanostructures with applications well beyond the field of SERS sensing.

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Large-area patterning of full-color quantum dot arrays beyond 1000 pixels per inch by selective electrophoretic deposition

Nature Communications ◽

10.1038/s41467-021-24931-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Jinyang Zhao ◽

Lixuan Chen ◽

Dongze Li ◽

Zhiqing Shi ◽

Pai Liu ◽

...

Keyword(s):

High Resolution ◽

Quantum Dot ◽

Electrophoretic Deposition ◽

Low Cost ◽

Great Promise ◽

Large Area ◽

Solution Processed ◽

Full Color ◽

Colloidal Quantum Dot ◽

Conventional Solution

AbstractColloidal quantum dot (QD) emitters show great promise in the development of next-generation displays. Although various solution-processed techniques have been developed for nanomaterials, high-resolution and uniform patterning technology amicable to manufacturing is still missing. Here, we present large-area, high-resolution, full-color QD patterning utilizing a selective electrophoretic deposition (SEPD) technique. This technique utilizes photolithography combined with SEPD to achieve uniform and fast fabrication, low-cost QD patterning in large-area beyond 1,000 pixels-per-inch. The QD patterns only deposited on selective electrodes with precisely controlled thickness in a large range, which could cater for various optoelectronic devices. The adjustable surface morphology, packing density and refractive index of QD films enable higher efficiency compared to conventional solution-processed methods. We further demonstrate the versatility of our approach to integrate various QDs into large-area arrays of full-color emitting pixels and QLEDs with good performance. The results suggest a manufacture-viable technology for commercialization of QD-based displays.

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Low-cost photodetector architectures fabricated at room-temperature using nano-engineered silicon wafer and sol-gel TiO2 – based heterostructures

Scientific Reports ◽

10.1038/s41598-019-54481-8 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Debika Banerjee ◽

Ivy M. Asuo ◽

Alain Pignolet ◽

Sylvain G. Cloutier

Keyword(s):

Low Cost ◽

Silicon Nanowire ◽

Sol Gel ◽

Nanowire Array ◽

Device Fabrication ◽

Visible Range ◽

Ambient Conditions ◽

Silicon Nanowire Arrays ◽

External Bias ◽

Wide Range

AbstractIn the last decades, significant research has been done on the nanocrystalline forms of titanium dioxide (TiO2). Amorphous TiO2 has not been studied intensively despite being significantly less expensive compared to crystalline TiO2. This study reveals significant improvement in UV-VIS photodetection properties from heterostructures fabricated in ambient environment using n-type silicon nanowire arrays and amorphous TiO2 sol-gel. Our ultra-low-cost UV-VIS photodetectors can cover a wide range of applications. We report fast rise/decay time constants of 0.23 ms/0.17 ms and high responsivity up-to 6.0 A/W in the UV and 25.0 A/W in the visible range under low (1 V) external bias. The large surface area due to the nanowire array architecture leads to 2 orders of magnitude enhancement in photo-response. Besides the final electrode deposition, the entire device fabrication is performed using low-cost, all solution-based methods in ambient conditions. These low-cost UV-Visible broadband photodetectors can potentially serve a wide range of applications.

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Long- and Short-Range Ordered Gold Nanoholes as Large-Area Optical Transducers in Sensing Applications

Chemosensors ◽

10.3390/chemosensors7010013 ◽

2019 ◽

Vol 7 (1) ◽

pp. 13 ◽

Cited By ~ 1

Author(s):

Maura Cesaria ◽

Adriano Colombelli ◽

Daniela Lospinoso ◽

Antonietta Taurino ◽

Enrico Melissano ◽

...

Keyword(s):

Self Assembly ◽

Short Range ◽

Low Cost ◽

Hexagonal Lattice ◽

Solid Substrate ◽

Attractive Alternative ◽

Large Area ◽

Glass Substrates ◽

Self Assembling ◽

Sensing Applications

Unconventional lithography (such as nanosphere lithography (NSL) and colloidal lithography (CL)) is an attractive alternative to sequential and very expensive conventional lithography for the low-cost fabrication of large-area nano-optical devices. Among these, nanohole (NH) arrays are widely studied in nanoplasmonics as transducers for sensing applications. In this work, both NSL and CL are implemented to fabricate two-dimensional distributions of gold NHs. In the case of NSL, highly ordered arrays of gold NHs distributed in a hexagonal lattice onto glass substrates were fabricated by a simple and reproducible approach based on the self-assembling of close-packed 500 nm diameter polystyrene particles at an air/water interface. After the transfer onto a solid substrate, the colloidal masks were processed to reduce the colloidal size in a controllable way. In parallel, CL was implemented with short-range ordered gold NH arrays onto glass substrates that were fabricated by electrostatically-driven self-assembly of negatively charged colloids onto a polydiallyldimethylammonium (PDDA) monolayer. These distributions were optimized as a function of the colloidal adsorption time. For both approaches, controllable and reproducible procedures are presented and discussed. The optical responses of the NH structures are related to the short-range ordering level, and their good performances as refractive index transducers are demonstrated.

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Exploring the Effect of Ammonium Iodide Salts Employed in Multication Perovskite Solar Cells with a Carbon Electrode

Molecules ◽

10.3390/molecules26195737 ◽

2021 ◽

Vol 26 (19) ◽

pp. 5737

Author(s):

Maria Bidikoudi ◽

Carmen Simal ◽

Vasillios Dracopoulos ◽

Elias Stathatos

Keyword(s):

Solar Cells ◽

High Efficiency ◽

Positive Impact ◽

Promising Result ◽

Low Cost ◽

Perovskite Solar Cells ◽

Precursor Solution ◽

Ammonium Iodide ◽

Ambient Conditions ◽

Large Area

Perovskite solar cells that use carbon (C) as a replacement of the typical metal electrodes, which are most commonly employed, have received growing interest over the past years, owing to their low cost, ease of fabrication and high stability under ambient conditions. Even though Power Conversion Efficiencies (PCEs) have increased over the years, there is still room for improvement, in order to compete with metal-based devices, which exceed 25% efficiency. With the scope of increasing the PCE of Carbon based Perovskite Solar Cells (C-PSCs), in this work we have employed a series of ammonium iodides (ammonium iodide, ethylammonium iodide, tetrabutyl ammonium iodide, phenethylammonium iodide and 5-ammonium valeric acid iodide) as additives in the multiple cation-mixed halide perovskite precursor solution. This has led to a significant increase in the PCE of the corresponding devices, by having a positive impact on the photocurrent values obtained, which exhibited an increase exceeding 20%, from 19.8 mA/cm2, for the reference perovskite, to 24 mA/cm2, for the additive-based perovskite. At the same time, the ammonium iodide salts were used in a post-treatment method. By passivating the defects, which provide charge recombination centers, an improved performance of the C-PSCs has been achieved, with enhanced FF values reaching 59%, which is a promising result for C-PSCs, and Voc values up to 850 mV. By combining the results of these parallel investigations, C-PSCs of the triple mesoscopic structure with a PCE exceeding 10% have been achieved, while the in-depth investigation of the effects of ammonium iodides in this PSC structure provide a fruitful insight towards the optimum exploitation of interface and bulk engineering, for high efficiency and stable C-PSCs, with a structure that is favorable for large area applications.

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Direct Metal Nano-patterning Using Embossed Solid Electrolyte

MRS Proceedings ◽

10.1557/proc-1156-d07-04 ◽

2009 ◽

Vol 1156 ◽

Cited By ~ 2

Author(s):

Anil Kumar ◽

Keng Hsu ◽

Kyle Jacobs ◽

Placid Ferreira ◽

Nicholas Fang

Keyword(s):

Solid State ◽

Solid Electrolyte ◽

Low Cost ◽

Ambient Conditions ◽

Large Area ◽

Micro Forming ◽

Metallic Substrates ◽

Tool Surface ◽

Electrochemical Imprinting ◽

Very High

AbstractThe recent growth in optoelectronics, nanoelectronics, nanooptics, and chemical and biological sensing has been fueled by the ability to fabricate nanostructures with ever smaller features. However, several significant constraints still remain in terms of cost, limited pattern size, processing conditions, pattern flexibility, and so on. Fabrication of features as small as 50 nm at ambient conditions with high pattern flexibility and low cost remains a serious challenge. Here we report a new solid-state electrochemical imprinting process that is carried out at ambient conditions, requires nominal pressure and very low electric potential, eliminates any liquid electrolytes, shows very high reproducibility, and promises the capability to scale up for large area patterning while retaining a significant cost advantage. Through combination of the best merits of nanoimprint lithography, micro forming, and the solid-state electrochemical imprinting technique, S4, (recently introduced by Hsu et al., Nano Lett., 2007, 7, 446; and Schultz et al., J. Vac. Sci. Techol. B, 2007, 25, 2419), we show a very high pattern flexibility to create nano-scale metallic features.As a first step, we use a micro-forming-like embossing process to engrave nano-scale features onto a solid electrolyte tool surface using an e-beam fabricated Si mold. Silver sulfide, Ag2S, is used as a solid electrolyte because of its favorable mechanical properties for micro forming and its excellent electrochemical properties. This ionic compound is ductile and has a relatively low yield stress at 80MPa. Followed by embossing, the patterned solid electrolyte surface is then used to carry out the S4 process, creating a negative image on a metallic substrate. This process eliminates the costly Focused Ion Beam milling used by Hsu et al. to create features on the electrolyte tool. It is also highly favorable for large-area patterning as well as mass-production of metallic substrates restricted only by the capability to fabricate the mold at first step. The embossed solid-electrolyte tool surface can be easily trimmed off with a microtome; the tool can then be re-used for embossing and patterning metallic substrates.Using this process we demonstrate the ability to fabricate silver nanostructures with features <15 nm. Such small features are critical in metal nanostructures for field enhancement that finds applications in SERS and other biological and chemical sensing. So far, a line edge roughness of <10 nm is observed which is significant in the sense that silver is highly mobile and has the tendency to granulate. Finally, we show how this methodology has the capability to fabricate large area patterns at low cost and ambient conditions. As a proof of concept, we demonstrate the ability to fabricate areas >30 sq. mm. Such large scale fabrication is highly desired for applications like biomimetics and patterning for superhydrophobic surfaces.

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Efficient Nanocrystal Photovoltaics via Blade Coating Active Layer

Nanomaterials ◽

10.3390/nano11061522 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1522

Author(s):

Kening Xiao ◽

Qichuan Huang ◽

Jia Luo ◽

Huansong Tang ◽

Ao Xu ◽

...

Keyword(s):

Solar Cells ◽

Active Layer ◽

Low Cost ◽

Treatment Temperature ◽

Ambient Conditions ◽

Large Area ◽

Deposition Parameters ◽

One Step ◽

Large Improvement ◽

Blade Coating

CdTe semiconductor nanocrystal (NC) solar cells have attracted much attention in recent year due to their low-cost solution fabrication process. However, there are still few reports about the fabrication of large area NC solar cells under ambient conditions. Aiming to push CdTe NC solar cells one step forward to the industry, this study used a novel blade coating technique to fabricate CdTe NC solar cells with different areas (0.16, 0.3, 0.5 cm2) under ambient conditions. By optimizing the deposition parameters of the CdTe NC’s active layer, the power conversion efficiency (PCE) of NC solar cells showed a large improvement. Compared to the conventional spin-coated device, a lower post-treatment temperature is required by blade coated NC solar cells. Under the optimal deposition conditions, the NC solar cells with 0.16, 0.3, and 0.5 cm2 areas exhibited PCEs of 3.58, 2.82, and 1.93%, respectively. More importantly, the NC solar cells fabricated via the blading technique showed high stability where almost no efficiency degradation appeared after keeping the devices under ambient conditions for over 18 days. This is promising for low-cost, roll-by-roll, and large area industrial fabrication.

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