Konrad Futera

Printed electronic on flexible and glass substrates

Organic electronics is a platform technology that enables multiple applications based on organic electronics but varied in specifications. Organic electronics is based on the combination of new materials and cost-effective, large area production processes that provide new fields of application. Organic electronic by its size, weight, flexibility and environmental friendliness electronics enables low cost production of numerous electrical components and provides for such promising fields of application as: intelligent packaging, low cost RFID, flexible solar cells, disposable diagnostic devices or games, and printed batteries [1]. The paper presents results of inkjetted electronics elements on flexible and glass substrates. The investigations was target on characterizing shape, surface and geometry of printed structures. Variety of substrates were investigated, within some, low cost, non specialized substrate, design for other purposes than organic electronic.

Polymer nanocomposites for screen printed electronic connections

Printed electronics makes possible to produce flexible electronic connections using printing techniques. This causes that printed items can be applied even on corrugated surfaces without any damages or changes in their properties. However, it is necessary to elaborate new materials which exhibited high flexibility. According to the results of investigations described in the literature nanomaterials, especially carbon nanotubes, allow to increase flexibility of printed layers. In the study, polymer nanocomposites for screen printed electronic interconnections were investigated. Carbon nanotubes, carbon nanofibres and silver nanopowder were used as fillers for elaborating of conductive pastes. Poly(methyl methacrylate) (PMMA), poly(methyl methacrylate)-poly(butyl methacrylate) (PMMA-PBMA) or conductive polymer PEDOT:PSS were applied as a carrier which was dissolved in an organic solvent butyl carbitol acetate. Elaborated polymer nanocomposites were printed on flexible substrate, like foil or paper. The resistance of specimens made with the paste with silver nanopowder was the lowest achieved value (below 100 mΩ/□). For the other pastes, it was equal significantly to above 150 Ω/□ and changed depending on a number of printed layers. The printed layers were also evaluated in terms of their durability to mechanical stresses. The smallest increase (2.65 %) in sheet resistance after 1000 bending cycles was observed for the layer printed with the paste containing silver nanopowder.

Influence of thermal cycling on reliability of solder joints executed on long and metal core PCBs

Purpose – The purpose of this paper is to evaluate the reliability of solder joints made on long FR-4 and metal core printed circuit boards using the accelerated thermal cycling. Design/methodology/approach – Solder joints of diodes and resistors samples made on long FR-4 and aluminum (Al) core printed circuit boards were examined. Two kinds of solder pastes were used for the samples preparation. All samples were subjected to temperature aging cycles (−40°C – 3 hours/+85°C – 3 hours). Solder joints resistance, X-Ray inspection and metallographic cross-sections for samples as received and after 100, 500 and 1,000 hours of thermal cycles were utilized for solder joints assessment. Findings – It was stated that 1,000 hours of thermal cycles were enough to show reliability problems in solder joints on long and/or AL core printed circuit board assembly (PCBA). The solder joints of R1206 components were the most sensitive reliability elements. The solder joints of LED diodes are more reliable than solder joints...

Characterization of polymer silver pastes for screen printed flexible RFID antennas

Radio Frequency Identification (RFID) systems have become more and more popular in the last few years because of their wide application fields, such as supply chain management and logistics. To continue their development further investigations of new conductive materials for fabrication of RFID transponders’ antennas are necessary to be carried out. These materials should provide high flexibility and good radiation performance of printed antennas. In this paper, two polymer silver pastes based on silver flakes were characterized with regard to manufacturing of flexible RFID antennas with screen printing technique. Foil and paper were used as a substrate materials. Surface profile of the printed antennas was measured using an optical profilometer and their resistance was measured with a four-point-probe method. Antenna flexibility was evaluated in cyclic bending tests and its performance with reflection coefficient measurements with the use of differential probe connected to a vector network analyzer. In addition, a maximum read distance of a fabricated RFID transponder was measured.

Mechanical and thermal reliability of conductive circuits inkjet printed on flexible substrates

Purpose This paper aims to present the results of investigations of inkjet-printed electronic circuits fabricated on a flexible substrate (KAPTON foil) using silver nanoparticles ink. Design/methodology/approach Fully inkjet-printed conductive circuit tracks were printed on a flexible, transparent KAPTON foil, using a commercial 40LT-15 C nanosilver ink as well as a PixDro LP50 inkjet printer with KonicaMinnolta 512 printhead. After cure, electrical properties by resistance measurements and printing quality by optical and SEM microscopic observation of conductive tracks were examined. Afterwards, the tested samples were annealed for 1, 2 and 3 h at 150°C or subjected to cycling bending. Findings It was found that silver nanoparticles ink could be used for the preparation of electronic circuits using the inkjet printing technique. The obtained patterns had appropriate mapping and good quality. It was also noticed that thermal annealing caused a decrease in resistivity values of the tested lines irrespective of their width. Approximately 34 per cent decrease was achieved in the values of resistivity of all the tested lines after the first hour of thermal annealing. After the second hour, the values of resistivity decreased by another 50 per cent. There were no visible changes in resistivity values after 1,000 cycles of bending. Originality/value In this paper, the results of thermal annealing and bending tests of inkjet-printed silver nanoparticle conductive tracks on flexible substrate were presented. That is very important information for producing printed circuit boards using ecological, rapid and low-cost inkjet printing techniques, particularly during the production of printed circuit boards on flexible substrates working in different conditions of mechanical and thermal stresses.

Modification of conductive polymer PEDOT:PSS layer by SWCNT

In this study, the effect of addition of single-walled carbon nanotubes (SWCNTs) on the morphological properties of poly(3,4-ethylenedioxythiophene/poly(4-styrenesulfonate) (PEDOT:PSS) has been investigated using scanning electron microscope (SEM) as well as the surface roughness evaluation by atomic force microscopy (AFM). The spin-coated films of PEDOT:PSS and PEDOT:PSS with addition of SWNTs (0.5 % by wt.) on glass were compared in our study. Experimental results show that surface roughness of PEDOT:PSS layers increases after addition SWNTs to the solution - from 3.50 nm for the samples without SWNTs to 4.65 nm for the samples with SWNTs. The analysis of SEM images showed that there are some agglomerations of SWNTs on the surface of PEDOT:PSS/SWCNT composite film.

Inkjet printed microwave circuits on flexible substrates using heterophase graphene based inks

Purpose – The purpose of this paper is to present the result of research on a new fabrication technology of printed circuits board and electronics modules. The new method is based on inkjet printing technique on flexible substrates using new generations of heterophase inks. New fabrications method was used to print microwave waveguides and signal splitters as new technology demonstrators. Design/methodology/approach – A fully Inkjet printed filter was printed on a flexible, transparent Kapton foil using heterophase inks developed in Instytut Technologii Materialow Elektronicznych (ITME) for the purpose of this research based on graphene and silver nanoparticles. Findings – A microwave module was printed using two types of Inkjet printers – PixDro LP50 with KonicaMinolta 512 printhead – and developed in an Instytut Tele- i Radiotechniczny (ITR) laboratory printer using MicroDrop a 100-μm glass nozzle printhead. Fully printed microwave circuits were evaluated by their print quality and electrical properties...

Low Cost Inkjet Printing System for Organic Electronic Applications

This work shows in details the design and performance of precise ink jet printing system which has been constructed for organic electronic technology analysis. The printing system was designed for laboratory investigation of inks and substrates compatibility. Printing system has been tested by its precision and abilities by fabrication electronic elements. PEDOT: PSS, Sun Tronic U6415, Nano silver based inks were tested. Glass, alumina ceramic, PEN foil and paper were tested as substrates. Printer was design in order to solve disadvantages of commercial systems. It has improved software with user friendly graphic interface, improved accuracy and precision. New drop watch solution has been develop. In the investigation, compatibility of materials and inks was tested. Methods of making inks and substrates compatible, by setting the substrate temperature, ink jet printhead voltage and geometry, were studied. Printed lines after sintering process become conductive. Ohmic resistance of lines was measured and their quality was evaluated.

Investigation of treated PEN foil surface properties for inkjet application

Purpose – The purpose of this paper is to report surface properties of treated Teonex Du Pont polyethylene naphthalate (PEN) foil substrates. Design/methodology/approach – There were three different cleaning treatments among other: argon glow discharge, dipping into alkaline solution at 60°C as well as washing in an ultrasonic bath of acetone and ethyl alcohol in room temperature. The relation between PEN foil morphology and surface properties has been studied by contact angle measurements as well as evaluation of surface roughness of PEN foil samples by atomic force microscopy (AFM). Findings – It was found that argon glow discharge (T3) of PEN treatment caused the maximum reduction in both values of contact angles. In addition, the argon glow discharge yielded the highest PEN surface energy (51.9 mJ/m2) and polarity (0.89). On the other hand, the AFM micrographs showed that the samples T3 had the highest value of average and root mean square surface roughness. Based on the experiments results, the autho...

Current-Voltage Characteristics and IR Imaging of Organic Light-Emitting Diodes

In this paper, a study of current-voltage characteristics and temperature distribution in the polymer organic light-emitting diodes are presented and discussed. The fabricated diodes consisted of ITO coated glass, PEDOT:PSS as a hole injection layer, one of eight different examined light-emitting compounds as an emissive layer, and aluminium cathode. The spectrum of light emitted by the fabricated OLEDs was also measured. Based on the results the most efficient.