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Summarization: This article presents European-based contributions for wireless power transmission (WPT), related to applications ranging from future Internet of Things (IoT) and fifth-generation (5G) systems to high-power electric vehicle charging. The contributors are all members of a European consortium on WPT, COST Action IC1301. WPT is the driving technology that will enable the next stage in the current consumer electronics revolution, including batteryless sensors, passive RF identification (RFID), passive wireless sensors, the IoT, and machine-to-machine solutions. The article discusses the latest developments in research by some of the members of this group. Presented on: IEEE Microwave Magazine

In this paper, a novel all-polymer integrated microsystem, which realizes a 2-D display by integrating a 1-D array of polymer light-emitting diodes (PLEDs) with a polymer scanner of microelectromechanical system (MEMS), is presented. Electronic modulation of PLEDs forms the first dimension of the display (fast scan), and the scanner actuation orthogonal to the direction of PLED lineup forms the second one (slow scan). MEMS scanner (actuator) is fabricated on a polymer composite (FR4 material) with a double-sided process using lithography to pattern copper lines and laser micromachining to cut the scanner outline. PLEDs are fabricated on polyethylene terephthalate sheets. They have a thin-film structure of indium tin oxide, poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate), poly [2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene], and aluminum. The scanner is actuated electromagnetically in its slow-scan resonance mode at 49 Hz, generating a maximum displacement of 3.5 mm at a drive power of 84 mW with the help of a mini permanent magnet attached to the tip of the scanner and an off-chip energizing coil. Turn-on voltage of a PLED is 7.5 V, and each one generate a luminance of 0.3 cd/m(2) at 13 V, consuming 1.1-mA current. Successful operation of the integrated-display system is shown by forming a checker box image with a resolution of 20 x 7 and a size of 9 mm by 3.4 mm.

This work presents post-fabrication electric field and heat treatment methods developed for polymer light emitting diodes (PLEDs). which have degraded due to exposure to oxygen and water vapors during low-cost fabrication performed in standard room conditions. Investigated PLEDs have structures composed of indium tin oxide (ITO), poly(3,4-ethylenedioxythiophene), poly(styrenesulfonate), (PEDOT:PSS), poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV), and aluminum (Al). Heat treatment restores the light emitting function of dysfunctional PLEDs but also causes a high turn-on voltage of 10 V. Electric field treatment utilizing -1 V reduces this high turn-on voltage to 3 V. This procedure also improves open circuit voltages from 5 mV to 55 mV, and short circuit currents from 0.5 nA to 5 nA when PLEDs are operated as photovoltaic cells under a light intensity of 500 mW/m(2). Repeated I-V sweep measurements additionally show improved stability and uniformity. The reasons for these improvements, the usage of an optimal treatment temperature of 130 degrees C, and the usage of treatment voltages of 0 and -1 V are discussed. (C) 2008 Elsevier B.V. All rights reserved.

Conjugated polymers are semiconductors that offer flexibility, simplicity and lower cost in the fabrication of polymer light emitting diodes (PLEDs), polymer transistors and circuits, polymer photodetectors and solar cells. They have a potential to lead to a technology that can monolithically integrate all the semiconductor devices mentioned above as well as polymer sensors and actuators. This paper presents a novel method as a post-fabrication treatment and its improvements over the performance of the light emitting and photovoltaic properties of PLEDs. Investigated PLED is made of indium tin oxide (ITO), poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and aluminum (Al). Following fabrication at room conditions, heat treatment is performed at 130C degrees for one hour and electric field treatment is realized with voltage levels from 0 to -8V under 0.2 atm vacuum. Heat treatment after fabrication restores the light emitting function of otherwise not functioning PLEDs, which degrade due to exposure to oxygen and water vapors at normal room conditions. Electric field treatment reduces the turn-on voltage of PLEDs when they are used as light emitting devices. Electric field treatment of -1 volt reduces the turn-on voltage to 3 volts from 10 volts, which is the case for the devices with heat treatment only. It also improves open circuit voltages and short circuit currents of PLEDs by an order of magnitude when they are used as photodetectors or photocells. Devices treated with heat only show a short circuit current of around 0.5 nA and open circuit voltage of 5 mV under 500 mW/m(2) light intensity. These values improve to 5 nA and 55 mV respectively after the devices are electrically treated with -1 volt. Electric field treatment after the thermal treatment also improves the stability and uniformity of the devices.