Search results for "electronics"

Coulomb blockade nanothermometer

1998

Reliable thermometry is normally based on commercial secondary sensors which are factory calibrated. Primary thermometers exist, too, but their use is limited because of intrinsic slowness, complex instrumentation, or inconvenient installation at the desired location. We have found that arrays of nanoscale tunnel junctions exhibit properties which are very suitable for primary and secondary cryogenic thermometry. Temperature range of this Coulomb blockade thermometer (CBT) extends over about two decades for one sensor and the mean temperature is lithographically adjustable. We have studied the performance of the CBT sensors at very low temperatures where the minimum temperature is limited b…

Dynamic preparation of TiO2 films for fabrication of dye-sensitized solar cells

2006

Preparation of nanocrystalline porous titanium dioxide (TiO2) films with roll-to-roll compatible methods was studied. Gravure printing was used for spreading TiO2 paste and paper calendering for pressing TiO2 nanoparticle films. Influence of different preparation methods on performance of fabricated dye-sensitized solar cells (DSSCs) was investigated. The attained light into electricity conversion efficiency was compared with DSSCs fabricated on conductive plastic substrates by doctor-blading spreading with subsequent static pressing. The latter method achieved a light conversion efficiency as high as 5.1%. The efficiency of the cells with a gravure printed TiO2 film was found to be rather …

Organoboron Polymers for Photovoltaic Bulk Heterojunctions

2010

We report on the application of three-coordinate organoboron polymers, inherently strong electron acceptors, in flexible photovoltaic (PV) cells. Poly[(1,4-divinylenephenylene)(2,4,6-triisopropylphenylborane)] (PDB) has been blended with poly(3-hexylthiophene-2,5-diyl) (P3HT) to form a thin film bulk heterojunction (BHJ) on PET/ITO substrates. Morphology may be modulated to give a high percentage of domains (10-20 nm in size) allowing exciton separation. The photoelectric properties of the BHJs in devices with aluminium back electrodes were imaged by light beam induced current (LBIC) and light beam induced voltage (LBIV) techniques. Open circuit voltages, short circuit currents and overall …

PEDOT:Poly(1-vinyl-3-ethylimidazolium) dispersions as alternative materials for optoelectronic devices

2008

Characterization of quantum dot/conducting polymer hybrid films and their application to light-emitting diodes.

2009

Quantum dot/conducting polymer hybrid films are used to prepare light-emitting diodes (LEDs). The hybrid films (CdSe@ZnS quantum dots excellently dispersed in a conducting polymer matrix, see figure) are readily prepared by various solution-based processes and are also easily micropatterned. The LEDs exhibit a turn-on voltage of 4 V, an external quantum efficiency greater than 1.5%, and almost pure-green quantum-dot electroluminescence.

Hybrids composites of NCCO/PEDOT for thermoelectric applications

2017

Abstract Organic materials are becoming a realistic roadway to fabricate efficient thermoelectric devices using environmental friendly materials. Such requirements are actually fulfilled by thermoelectric generators operating by conducting polymers, but also by hybrid materials. The combination of organic + inorganic compounds may exhibit a high electrical conductivity and Seebeck coefficient as well as lower thermal conductivity in order to efficiently generate thermoelectric power. In these hybrid compounds, perovskite-type oxides are a suitable election for the inorganic part since they have a high Seebeck coefficient although their electrical conductivity is usually low. Blending them w…

Structural control of mixed ionic and electronic transport in conducting polymers

2016

Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate), PEDOT:PSS, has been utilized for over two decades as a stable, solution-processable hole conductor. While its hole transport properties have been the subject of intense investigation, recent work has turned to PEDOT:PSS as a mixed ionic/electronic conductor in applications including bioelectronics, energy storage and management, and soft robotics. Conducting polymers can efficiently transport both holes and ions when sufficiently hydrated, however, little is known about the role of morphology on mixed conduction. Here, we show that bulk ionic and electronic mobilities are simultaneously affected by processing-induced change…

Solution processable high band gap hosts based on carbazole functionalized cyclic phosphazene cores for application in organic light‐emitting diodes

2011

A new class of solution processable dendrimers based on cyclic phosphazene (CP) cores have been prepared and used as host materials for blue and green organic light emitting diodes (OLEDs). The dendrimers are prepared in high yield from minimal step reactions, are soluble in common solvents for solution processing, are amorphous, and have excellent thermal properties necessary for application in OLEDs. OLED efficiencies of 10.3 cd/A (4.2 Im/W) and 35.3 cd/A (33.5 Im/W) were achieved using commercially available Flrpic and Ir(mppy) 3 as blue and green phosphorescent emitters, respectively. These efficiencies were 2x higher than control devices prepared using poly(N-vinylcarbazole), the most …

Influence of device geometry on sensor characteristics of planar organic electrochemical transistors.

2009

The response of PEDOT:PSS planar electrochemical transistors to H2O2 can be tuned by varying the ratio between the areas of the channel and the gate electrode. Devices with small gates show lower background signal and higher sensitivity. The detection range, on the other hand, is found to be rather independent of the gate/channel area ratio.

Optical properties of biocompatible polyaniline nano-composites

2006

Abstract Polyaniline (PANI) is an electro-active polymer of great interest thanks to its outstanding physical and chemical properties which make it suitable for various applications in optics, bioelectronics, biosensors, diagnostics and therapeutic devices. Unfortunately, PANI is infusible and insoluble in most common solvents and, thus, very difficult to process. In the attempt of improving processability, yet preserving its interesting properties, PANI has been synthesized in the form of particles and dispersed into a hydrogel matrix. The synthesis of PANI–hydrogel composites proceeds via γ-irradiation of PANI dispersions as obtained by ‘in situ’ polymerization of aniline in the presence …