Clint Landrock

Large-Area Low-Cost Flexible Plastic Nanohole Arrays for Integrated Bio-Chemical Sensing

Detection of plasmonic resonance peak shifts of nano-structured metamaterials is a promising method for sensing bio-chemical binding events. Although the concept is widely demonstrated in the laboratory environment using surface nano-structures machined at low-throughput and high-costs, practical solutions for high-volume production of an integrated sensing device are very limited. We present a concept of an integrated architecture that combines a thin layer of plasmonic nanohole sensing arrays, organic light-emitting diode illumination source, and microfluidic chip, for point-of-care, field, or lab applications. We discuss the fabrication of the sensor components. In particular, we present the improved fabrication of master nano-structure replication stamps, and demonstrate outstanding results for producing singular sheets or scale up to roll-to-roll embossing of nanohole arrays on a 2000 ft production roll. We further demonstrate that nanohole arrays embossed on flexible polyethylene terephthalate plastic sheets, when coated with 100 nm thin Au metal film, are capable of generating average plasmonic resonance shifts of 180 nm refractive index unit. Hence, we report the extraordinary transmission and plasmonic resonance shifts of nanohole arrays fabricated on roll-to-roll plastic sheets for the very first time. Our results show that the embossed nano-structures on plastic are suitable as sensor elements in our proposed integrated sensor architecture, and a promising technology for low-cost disposable applications.

An Improved Light Source Using Filtered Tungsten Lamps as an Affordable Solar Simulator for Testing of Photovoltaic Cells

An improved Tungsten light source system for photo voltaic cell testing constructed from low-cost, commercially available materials is presented as an alternative to current high-cost solar simulators. In this work, spectral correction of the Tungsten light source is achieved by increasing the colour temperature to ~5200 K using inexpensive commercially available filters. Spectral measurements of the corrected light source reveal that a better spectrum match towards the solar spectrum is achieved than what has been previously demonstrated by our team. Specifically, the improved solar spectrum match is achieved by substantial filtering of the infrared range. The proposed setup is used to evaluate the performance of both silicon and organic based solar cells.

Method of fabricating a convenient light source and its evaluation in PV cell laboratory testing

This paper presents a simple method of fabricating a controlled light source for photovoltaic cell testing using commercially available materials, as a

Towards Self-Powering Touch/Flex-Sensitive OLED Systems

In this work, we present a novel design for an organic light-emitting system integrated with a mechanical energy harvesting and energy storage polymer films (patent pending). The system is configured into multiple stacked layers to form a thin, flexible, and lightweight assembly. The thin “film-like” device can be deformed and flexed to generate energy up to 0.5 mW within 100 s with ease. This platform technology finds applications in energy harvesting displays, electronic papers, key-input-pads, novel packaging, smart-IDs, disposable lab-on-a-chip optomicrofluidic systems, and much more. Results on the energy storage characteristics of the ionic polymer-metal composite film, the performance of a polyfluorene-based organic light-emitting device, and the mechanical energy transduction of the piezoelectric polymer energy harvester are presented. The polymeric nature of this platform system further makes it suitable for roll-to-roll print manufacturing, supporting applications requiring high volume and low cost.

Platform for all-polymer-based pulse-oximetry sensor

The high risk of fatal infections via inappropriately disinfected medical equipment in operative scenarios are progressively prompting for better sterilization procedures in reusable equipment. The cost for thoroughly decontaminating skin-contact medical equipment such as finger-tip pulse oximeters after each use can cost hospitals several dollars per use per device; however, disposable pulse oximeter sensors at appropriately low cost can significantly alleviate healthcare expenses while virtually eliminating the risk of infections. A polymer-based pulse oximeter sensor unit that can replace traditional reusable finger-tip sensors is proposed. The unit consists of an organic photosensor module co-fabricated with an organic light-emitting-diode module under a single process on a polymer substrate. The platform is lightweight, flexible, robust, and potentially recyclable. The design considerations, architecture, and preliminary device performance results are presented. The all-polymer nature of the system promises opportunity to manufacture disposable pulse oximeter sensors at favorably low costs to replace traditional sensor clips.

Towards self-powering touch-sensitive OLED systems

In this paper, we present a novel design of an OLED system that is integrated with a mechanical energy harvesting polymer film and energy storage polymer film (patent pending). The system is configured in multiple stacked layers to form a thin, flexible, and light-weight assembly, for applications in energy harvesting displays, electronic papers, touch-input-pads, novel packaging, and much more. Initial results on the energy storage characteristics of the polymer film, the performance of a polyfluorene based OLED, and discussions on the mechanical energy transduction are presented.

Experimental and Numerical Analysis of Extraordinary Optical Transmission through Nano-hole arrays in a thick metal film

In this paper, we present experimental and numerical analysis on Extraordinary Optical Transmission (EOT) through various nano-hole arrays in a thick metal film within the visible and near infra-red spectrum of light. Large nano-hole arrays with different spacing between adjacent holes in the square lattice arrangement were fabricated using Electron Beam Lithography (EBL). Optical transmission properties (wavelength, peak, and spectral bandwidth of transmission resonances) of the fabricated nano-hole arrays were characterized and validated by numerical analysis based on Finite Difference Time Domain (FDTD). Finally, the dependencies and discrepancies between EOT properties of various nanohole arrays were analyzed.

Optical response of large-area aluminum-coated nano-bucket arrays on flexible PET substrates

The high-cost of fabrication of nanohole arrays for extraordinary optical transmission, surface-plasmon-resonance-based sensors, inhibits their widespread commercial adoption. Production typically involves the application of small-area patterning techniques, such as focused-ion-beam milling, and electron-beam lithography onto high-cost gold-coated substrates. Moving to lower-cost manufacturing is a critical step for applications such as the detection of environmental oil-leaks, or water quality assurance. In these applications, the sensitivity requirements are relatively low, and a bio-compatible inert surface, such as gold, is unnecessary. We report on the optical response of aluminum-coated nano-bucket arrays fabricated on flexible polyethylene terephthalate substrates. The arrays are fabricated using an economical roll-to-roll UV-casting process from large sheets of nickel templates generated from master quartz stamps. The nano-featured surface is subsequently coated with 50 nm of thermally-evaporated aluminum. The roll-to-roll production process has a 97% yield over a 600 m roll producing nano-buckets with 240 nm diameters, 300 nm deep, with a 70° taper. When exposed to a series of refractive index standards (glucose solutions), changes in the locations of the resonance transmission peaks result in optical sensitivities as high as 390 ± 20 nm/RIU. The peak transmission is approximately 5% of illumination, well within the sensitivity requirements of most common low-cost detectors.

Towards future systems with nano-optics contributions

The long anticipated deployment of nano-optics that can enable next generation computing has encountered several practical impediments that have delayed widespread adoption in commercial processes. However, the global market in nano-enabled products is expected to grow to over

Rapid fabrication of nano-structured quartz stamps

80B USD within the next 3 years. In response, the research community is creating solutions to overcome challenging issues such as reliability and cost-effective fabrication. New approaches in sensing, continuous uptime powering, and post silicon manufacturing will maximize overall performance and allow unprecedented commercial applications. This paper reviews present limitations of nano-optics and then considers the new generation of devices and their manufacturing that may turn promises into reality. We highlight several recent innovations: high sensitivity/selectivity nano-optical sensing devices; sustainable power from polymer energy harvesting and storage; optical variable devices for visual authentication of secure documents; and nano-template masters for high-volume manufacturing.