Disposable Heater Arrays Using Printed Silver Patterns on Polyethylene Terephthalate for Multipurpose Applications

Abstract

Flexible, semitransparent and robust heating arrays have been designed by grayscale printing as ready‐to‐use devices for point‐of‐care application. A perforated Ag mesh is first fabricated with tunable features by controllably varying the toner grayscale value during laser printer on PET. The resistance could be varied between 1 to 2 Ω by tuning the Ag fill factor from 50 to 70 %. The Ag/PET heater based on joule heating is able to attain highly stable temperatures upto ∼135 °C maintained over long hours. Since temperature is directly related to resistance, this provides a fine temperature knob without any cumbersome processing steps. The merit of design allows individual heating elements to attain stable temperatures at low voltages (∼1.5 V) without any interference from neighboring heaters of the array, thus resulting in a thermal library. A laptop USB with 5.1 V output is able to power the thermal library for temperatures in the range of 30–60 °C, useful in many practical applications. It is a multipurpose disposable chip for in‐situ transmission microscopy that can be utilized for bioassay and point‐of‐care diagnostics, as demonstrated in the study.

Microscopic Evaluation of Electrical and Thermal Conduction in Random Metal Wire Networks

“…Transparent and flexible conducting films are essential for modern devices such as touch screens, solar cells, organic light-emitting diodes, and transparent heaters . In particular, transparent heaters , play an important role in the defogging and defrosting of display panels, windows of automobiles, and lenses of optical instruments. Further, the combination of optical transparency and the controlled application of heat are essential for devices that require a uniform operating temperature, such as transparent heaters, transparent sensors, and liquid-crystal displays (LCDs) .…”

“…In particular, transparent heaters , play an important role in the defogging and defrosting of display panels, windows of automobiles, and lenses of optical instruments. Further, the combination of optical transparency and the controlled application of heat are essential for devices that require a uniform operating temperature, such as transparent heaters, transparent sensors, and liquid-crystal displays (LCDs) . Transparent heaters use Joule heating to control the temperature; hence, the films should have both high optical transmittance and low sheet resistance.…”

“…The thermal response of transparent heater networks has predominantly been studied using noncontact methods such as infrared (IR) thermography. ,, The spatial and temporal resolutions of such cameras limit the measurement to local average temperatures. However, many projected applications of transparent heaters, such as temperature-dependent spectroscopy and studies of reactions on heater stages, require knowledge of the local temperature profile with precise spatial and temporal resolutions . For accurate local temperatures, the wire width must be larger than the spatial resolution of the imaging system.…”

Inkjet Printed Heating Elements Based on Nanoparticle Silver Ink with Adjustable Temperature Distribution for Flexible Applications

“…[ 25 ] Other methods are spray coating of Ag nanowire/carbon nanotube composites [ 26 ] or patterned casting of Ag on flexible polymer foil . [ 27 ] Such printed flexible heaters find their application in wearable thermotherapy pads, [ 28 ] paper diagnostics, [ 29 ] and other wearable applications. [ 30 ] Moreover, only a few publications can be found in the field of inkjet printed heaters such as Byers et al with silver microheaters, [ 29 ] Wang et al with silver nanowire flexible transparent heaters, [ 31 ] or Huang et al with silver nanowires for stretchable heaters.…”

Work function tunable metal-mesh based transparent electrodes for fabricating indium-free organic light-emitting diodes

“…Moreover, with the right choice of the metal, the workfunction of the m-TCE can be tuned to suit the application. Thus, m-TCEs with different workfunctions have been successfully employed as transparent electrodes of organic solar cells and touchscreens [12,[15][16][17].…”