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

Chemosensors ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 13 ◽  
Author(s):  
Maura Cesaria ◽  
Adriano Colombelli ◽  
Daniela Lospinoso ◽  
Antonietta Taurino ◽  
Enrico Melissano ◽  
...  

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.

2020 ◽  
Vol 90 (3) ◽  
pp. 30502
Author(s):  
Alessandro Fantoni ◽  
João Costa ◽  
Paulo Lourenço ◽  
Manuela Vieira

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.


2019 ◽  
Vol 4 (3) ◽  
pp. 580-585 ◽  
Author(s):  
Bineh G. Ndefru ◽  
Bryan S. Ringstrand ◽  
Sokhna I.-Y. Diouf ◽  
Sönke Seifert ◽  
Juan H. Leal ◽  
...  

Combining bottom-up self-assembly with top-down 3D photoprinting affords a low cost approach for the introduction of nanoscale features into a build with low resolution features.


Author(s):  
Sreekanth Mandati ◽  
Prashant Misra ◽  
Divya Boosagulla ◽  
Tata Naransinga Rao ◽  
Bulusu V. Sarada

Abstract Electrodeposition is one of the leading non-vacuum techniques for the fabrication of CuInSe2 (CIS)-based solar cells. In the present work, pulse electrodeposition, an advanced technique, is utilized effectively for CIS absorber preparation devoid of any additives/complexing agents. An economic pulse electrodeposition is employed for the deposition of Cu/In stack followed by selenization to fabricate CIS absorbers on flexible and glass substrates. The approach uses a two-electrode system suitable for large area deposition and utilizes the fundamentals of pulse electrodeposition with appropriate optimization of parameters to obtain smooth Cu/In precursors. The selenized CIS absorbers are of 1 µm thick while possessing copper-poor composition (Cu/In ≈ 0.9) and tetragonal chalcopyrite phase. The fabricated devices have exhibited a power conversion efficiency of 5.2%. The technique can be further improved to obtain low-cost CIS solar cells which are suitable for various small-scale energy applications.


2014 ◽  
Vol 528 ◽  
pp. 112-117
Author(s):  
Chao Rong Li ◽  
Hu Yang ◽  
Juan Li

Water/toluene interfacial self-assembly of nanostructures is a powerful bottom-up approach for film fabrication because of the low cost and high efficiency, and it is a simple and universal method for almost all low-dimensional nanostructures. The method involved adding alcohol and then toluene (here the dispersant was itself alcohol, only toluene was added) into SiO2 nanoparticle dispersion, and then a large quantity of distilled water was rapidly poured into the mixed system. Simultaneously, nanoparticles in the dispersion were extracted to the water/toluene interface, forming a thin film with a nearly perfect hexagonal close packed phase. Large-area nanoparticle monolayer films (e.g., more than 20 cm2) could be prepared in less than 1 min. The close-packed structures of these thin films were verified by a field emission scanning electron microscopy (FESEM, Hitachi S-4800, Japan). We also investigated the whole process of forming the films and found out the mechanism of water-induced interfacial assembly. As for the specific kinetic mechanism of the fabrication process, it is expected to further study in later time.


2018 ◽  
Vol 6 (20) ◽  
pp. 5473-5481 ◽  
Author(s):  
Chithra Parameswaran ◽  
Dipti Gupta

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.


2001 ◽  
Vol 124 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Swapan K. Bhattacharya ◽  
Rao R. Tummala

Polymer/ceramic composite emerges as a novel material system for application as integral capacitors for the next generation of microelectronic industry where the discrete passive components such as capacitors, resistors, and inductors are likely to be replaced by the embedded components. In this study, epoxy based nanocomposites are selected due to their low-cost and low temperature processing advantages in comparison to the traditional polymers used in the microelectronic industry today. Other potential advantages of epoxy materials could be their aqueous based fabrication process and availability in the form of dry films for direct lamination onto substrates. This paper reports dielectric properties of epoxy nanocomposites made from three commercially available resin composites (i) a solvent based photodefinable epoxy, (ii) an aqueous based photodefinable epoxy, and (iii) a non-photodefinable epoxy. Possible avenues for achieving higher capacitance density in polymer/ceramic composites for future needs have been discussed. Deposition of polymer/ceramic thin films on a 300 mm×300 mm PWB and glass substrates has been demonstrated using a state-of-the-art meniscus coater. The end goal of this study is to develop a defect-free manufacturable process for depositing and patterning particulate epoxy composite capacitors on large area PWB substrates. It is believed that the large area process will reduce the overall manufacturing costs and increase process yield, thus facilitate the economic viability of the integral passive technology.


Coatings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 183 ◽  
Author(s):  
Guobin Jia ◽  
Jonathan Plentz ◽  
Jan Dellith ◽  
Andrea Dellith ◽  
Ruri Wahyuono ◽  
...  

Graphene and its derivatives have many superior electrical, thermal, mechanical, chemical, and structural properties, and promise for many applications. One of the issues for scalable applications is the lack of a simple, reliable method that allows the deposit of a well-ordered monolayer using low-cost graphene flakes onto target substrates with different surface properties. Another issue is the adhesion of the deposited graphene thin film, which has not been well investigated yet. Following our former finding of a double self-assembly (DSA) process for efficient deposition of a monolayer of graphene flakes (MGFs), in this work we demonstrate that the DSA process can be applied even on very challenging samples including highly hydrophobic polytetrafluoroethylene (PTFE), flexible textiles, complex 3D objects, and thin glass fibers. Additionally, we tested adhesion of the graphene flakes on the flat glass substrate by scotch tape peel test of the MGFs. The results show that the graphene flakes adhere quite well on the flat glass substrate and most of the graphene flakes stay on the glass. These findings may trigger many large-scale applications of low-cost graphene feedstocks and other 2D materials.


2015 ◽  
Vol 804 ◽  
pp. 183-186
Author(s):  
Prapon Lertloypanyachai ◽  
Eakgapon Kaewnuam ◽  
Krittiya Sreebunpeng

Titanium dioxide (TiO2) is coated onto the materials (e.g.glass ceramic) to inhibit the bacteria growth. TiO2has become a popular photocatalyst for both air and water purification. It has also shown to be very active for bacterial destruction even under UV light. The photocatalytic of TiO2involves the light-induced catalysis of reducing and oxidizing reactions on the surface of materials. The spray pyrolysis technique for material synthesis in thin-film configuration is an interesting option due to the use of inexpensive precursor materials and low-cost equipment suitable for large-area coatings. In this research, TiO2thin films were deposited onto glass substrates using spray pyrolysis technique. Escherichia coli (E.coli) was used as testing bacteria. TiO2thin films showed some antibacterial effect in the halo test.


2011 ◽  
Vol 483 ◽  
pp. 48-52
Author(s):  
Fan Tao Meng ◽  
Jin Kui Chu ◽  
Gang Luo ◽  
Zhi Tao Han ◽  
Zhi Wen Wang

Flexible polymer stamps are considered as an attractive alternative to rigid, brittle and expensive stamps made of inorganic materials because of their low cost and ease of fabrication. In this paper, we present a nanoimprint process to fabricate large area, high-resolution nanograting patterns using flexible polymer stamp made from fluoropolymer. The flexibility and low surface energy of polymer stamp provide a clean release without fracture or deformation of the stamp and of the replicated nanograting. Large-area, high-density nanograting patterns with good shape homogeneity and size uniformity have been successfully fabricated using the flexible polymer stamp with advantages of its good conformal contact and low adhesion. Using flexible polymer stamps can resolve many serious issues in NIL and therefore can bring it to real industrial applications.


2012 ◽  
Vol 2012 (1) ◽  
pp. 000935-000939
Author(s):  
Yiliang Wu ◽  
Ping Liu ◽  
Tony Wigglesworth

Printable conductors with high conductivity would be critical for low-cost printed electronics. In view of printability, conductivity, and electrical stability, metal such as gold or silver derived from solution-deposited precursor compositions would be an ideal candidate. Xerox has been exploring the use of silver nanoparticles as conductor precursor composition for printed electronics. This paper reviews our research in the development of alkylamine-stabilized silver nanoparticles that can be sintered at low temperature (∼ 120 °C) for high conductivity (>10000 S/cm). Silver nanoparticle ink formulations based on these silver nanoparticles exhibit surface-energy independent printability which enables the fabrication of high-performance top-contact transistor devices, and self-assembly characteristic when printed on hydrophilic substrates which allows for large-area, defect-free source drain arrays to be printed with a narrow and uniform channel length.


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