we report about the fabrication of organic light-emitting diodes (OLEDs) ink-jet printing a hole-transporting polymer (PF6, poly(9,9-dihexyl-9H-fluorene-2,7-diyl)) on flexible substrate (PET) and performing the other layers through vacuum thermal evaporation. The aim of the work is to employ the ink-jet printing (IJP) technology, familiar as a method for printing on paper, in optoelectronic applications and to determine how the deposition method affects the functional material film properties and hence the ultimate device performances. In this line of work, ink-jet printed polymer films are compared to same spin-coated polymer from the electro-optical point of view: both prepared materials are adopted as HTLs of electroluminescent devices. All manufactured OLEDs are characterized and their behaviours are investigated and analyzed with theoretical models. The results show differences in current density and optical behaviours between the devices fabricated by means of the above mentioned technologies which can be justified in terms of different trap distribution induced by impurity energy levels associated to each process. 相似文献
Amorphous SixC1-x thin films have been grown by low-pressure chemical vapour deposition at 800 K from Si2H6 and C2H2 in the x concentration range 0.5≤x<0.7. Measurements of the valence-band and core-level photoemission spectra using X-ray photoemission spectroscopy and synchrotron radiation have shown a clear change in the electronic structure for 0.55xC1-x films obtained by excimer laser annealing during growth have shown the formation of a dominant 3C-SiC phase up to x=0.6, while for higher x the growth of a poly-Si phase has been observed . PACS 81.15.Gh; 79.60.Dp 相似文献
The investigation of a method for fabricating microlenses by a nozzle-free inkjet printing approach is reported. The new method, based on a pyroelectrohydrodynamic mechanism, is also able to dispense viscous liquids and to draw liquid phase drops directly from the reservoir. Specifically, by dispensing optical grade polymer dissolved in different solvent mixtures, microlenses were printed with a pattern defined directly through this deposition method. The reliability of the microlenses and the tunability of their focal properties were demonstrated through profilometric and inteferometric analyses. 相似文献
In this paper we present and discuss experimental results to evaluate performances and aging behaviour of two Hole Transporting Material (HTM), TPD and NPD, in Organic Light Emitting Device (OLED) with structure: ITO/HTM/Alq3/Al. For each of these HTMs, devices with several thicknesses have been built, to measure and emphasize behaviours of material-geometry combinations. Electro-optical properties have been measured to estimate and compare brightness, power efficiency and aging decays. 相似文献
The integration of semiconductor nanoparticles (NPs) into a polymeric matrix has the potential to enhance the performance
of polymer-based solar cells taking advantage of the physical properties of NPs and polymers. We synthesize a new class of
CdS-NPs-based active layer employing a low-cost and low temperature route compatible with large-scale device manufacturing.
Our approach is based on the controlled in situ thermal decomposition of a cadmium thiolate precursor in poly(3-hexylthiophene)
(P3HT). The casted P3HT:precursor solid foils were heated up from 200 to 300 °C to allow the precursor decomposition and the
CdS-NP formation within the polymer matrix. The CdS-NP growth was controlled by varying the annealing temperature. The polymer:precursor
weight ratio was also varied to investigate the effects of increasing the NP volume fraction on the solar cell performances.
The optical properties were studied by using UV–Vis absorption and photoluminescence (PL) spectroscopy at room temperature.
To investigate the photocurrent response of P3HT:CdS nanocomposites, ITO/P3HT:CdS/Al solar cell devices were realized. We
measured the external quantum efficiency (EQE) as a function of the wavelength. The photovoltaic response of the devices containing
CdS-NPs showed a variation compared with the devices with P3HT only. By changing the annealing temperature the EQE is enhanced
in the 400–600 nm spectral region. By increasing the NPs volume fraction remarkable changes in the EQE spectra were observed.
The data are discussed also in relation to morphological features of the interfaces studied by Focused Ion Beam technique. 相似文献
studies on the influence of chemical and physical treatments on the properties of indium–tin oxide (ITO) thin films are reported. The ITO films are utilized as transparent anodes of organic light-emitting diodes (OLEDs) incorporating poly(9,9-dihexyl-9H-fluorene-2,7-diyl) (PF6) as the hole transporter material and 8-hydroxyquinoline aluminum salt (Alq3) as emitter material. Chemical (HCl, piranha solutions), thermal (vacuum annealing), physical treatments (oxygen plasma, UV ozone) and combined treatments are studied. First, ITO layers with different treatments are characterized by using four point probe method, contact angle measurement, X-Ray diffraction (XRD), surface profilometer, scanning electron microscopy (SEM), UV-Vis-IR transmittance. Later, electrical and optical properties of OLEDs with treated ITO as anode are extensively investigated. 相似文献
A novel study about the synthesis of zirconia and calcia-stabilized zirconia powders were carried out by DC thermal plasma starting from cheap precursors as the carbonates. Different operational parameters were investigated to explore the effects of the process conditions, such as the plasma torch power and the gas flow rate on the composition and the morphology of the powders. The products phase changes from a metastable tetragonal to monoclinic/tetragonal mixture. Basically a main tetragonal phase was obtained at low torch power (7 kW) while the amount of monoclinic phase linearly rises with the power, up to 66 wt% at 26 kW of plasma power and high gas flow rate. The gas flow rate also affects the shape and the size of the powder, where high values reduce powder aggregation and enhance the spherical shape. The best results were achieved at 22 kW of plasma power and high gas flow rate, with powders of roundness about 79% and a wide particle size distribution. Adding the calcium carbonate to the zirconium carbonate (corresponding to 8 wt% CaO in the final mixture), the plasma treatment mainly produces a tetragonal phase zirconia, that at 1400 °C in furnace changes in a stable cubic phase. These powders could be made suitable for further industrial applications after proper treatments.