The S-shaped J-V curves in planar heterojunction organic solar cells (OSCs) using triplet material bis[2-(4-
tertbutylphenyl)benzothi azolato-N, C2,] iridium (acetylacetonate) [(t-bt)2Ir(acac)] as donor and C60 as acceptor were diminished by substrate heating during film deposition of (t-bt)2Ir(acac) layer. Mobility measurements showed that the disappearance of S-kinks was attributed to the significant increase of hole mobility in (t-bt)2Ir(acac) by heating the substrate during evaporation and thus the decrease of mobility mismatch between electrons and holes, leading to the improvement of fill factor (FF). Moreover, the photocurrent density (Jph) of heated device was remarkable enhanced and showed decreased space charge limited (SCL) effect due to the balanced charge transport and the increase of charge collection efficiency (ηCC). As a result, by heating the substrate at 70 ℃, a power conversion efficiency (PCE) of 1.63 % was achieved compared to 1.37 % for the unheated device. Using this method, organic solar cells based on triplet materials allow thicker active layer thickness for light absorption without introducing much fill factor loss.
Proc. SPIE. 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology
White organic lighting-diode (WOLED) can be used as flat light sources, backlights for liquid crystal displays and full
color displays. Recently, a research mainstream of white OLED is to develop the novel materials and optimize the
structure of devices. In this work a WOLED with a structure of ITO/NPB/PAA/Alq3: x% rubrene/Alq3/Mg: Ag, was
fabricated. The device has two light-emitting layers. NPB is used as a hole transport layer, PAA as a blue emitting layer,
Alq3: rubrene host-guest system as a yellow emitting layer, and Alq3 close to the cathode as an electron transport layer. In
the experiment, the doping concentration of rubrene was optimized. WOLED 1 with 4% rubrene achieved a maximum
luminous efficiency of 1.80 lm/W, a maximum luminance of 3926 cd/m2 and CIE coordinates of (0.374, 0.341)
.WOLED 2 with 2% rubrene achieved a maximum luminous efficiency of 0.65 lm/W, a maximum luminance of
7495cd/m2 and CIE coordinates of (0.365,0.365).
A type of optical constants measuring system controlled by a computer was developed. The system consists of a focusing lens, a monochromator that is composed of a diffraction grating and a photomultiplier, a high-precision voltage amplifier, a level buffer circuit, a data-sampling card composed of a A/D converting circuits, a interrupt circuit and I/O interface circuits and a PC. The heart of the system is a PC, which is served as data sampling, processing and calculating unit. The transmission spectrum of α:H silicon film is measured by this system. Then, a kind of envelopes calculation method proposed by Manifacier is used to calculate refractive index, absorptive coefficient and optical band. The accuracy is of the same orders as for the iteration method.
A 1.8-in. high-resolution passive matrix OLED (PMOLED) display panel has been successfully developed. We design the structure of full color PMOLED device. We pattern the device on a 128×3×160 pixel area, 384 row ITO anodes and 160 column cathode separators on ITO glass developed by us through photolithograph process. We have successfully fabricated the 1.8-in. 128×160 full color passive OLED display panel through our SUNICEL PLUS 200 OLED systems. The structure of OLED is a double-hetero structure. It has the device structure of ITO/2TNATA/NPB/ Alq3+C545T/Alq3/LiF/Al for green, ITO/2TNATA/ NPB/Alq3+Rubrene+DCJTB/ Alq3/LiF/Al for red, ITO/2TNATA/
NPB/EB43+TBPE/Alq3/LiF/Al for blue. The PMOLED display panel has full color emission with a resolution of 128×160, and the brightness of 200 cd/m2, as well as the lifetime of 5000 hours. The open aperture ratio of each pixel is 45%.
A novel light absorption layer for liquid crystal light valve is developed by VOPc and a new structure of liquid crystal light valve by using a three-sources evaporation system is proposed. CdTe is a typical absorption layer for liquid crystal light valve, but its absorption coefficient is not so good, especially at 400nm-500nm. However, the absorption of VOPc is very good at this range. So VOPc is introduced to the multi absorption layer. Then a double-layer absorption layer with a good absorption at whole visible light range can be got. To increase the adherence to the substrate, an SiO layer is introduced to wrap the CdTe layer and VOPc layer like a sandwich structure. At first SiO layer is evaporated and then the CdTe layer and the VOPc layer at the same time. After finishing the CdTe layer, VOPc is continuously evaporated for a while and then evaporating the CdTe is again made. After finishing CdTe and VOPc layer, SiO layer is used to cover the whole layer. At last, a multi light absorption layer with 8000Å thick and the structure of SiO:CdTe:VOPc:CdTe:SiO is deposited on glass by evaporation technique. Dependence of light absorption coefficient of multi film is measured. The resistivity of novel absorption layer is 5.5 108Ω•cm. The absorption coefficient of R=7.8 105 cm1, G=6.8 105 cm1, and B=7.2 105 cm1 is obtained with the optimum technics through experiment, and it can meet the needs of the liquid crystal light valve.
We deposited indium tin oxide (ITO) films on glass substrates with DC magnetron sputtering system and the experiments were scheduled by orthogonal test table L32(48). Sheet resistance, surface morphology and transmittance of films were tested. Effects of eight parameters on electrical and optical properties of ITO films, were discussed in detail. Deposition pressure, flow ratio of argon to oxygen and annealing temperature will greatly affect conductance of ITO films. The best parameters for sputtering ITO are: deposition pressure 2mTorr, flow ratio of argon to oxygen 16:0.5, annealing temperature 700K, distance between target and substrate 15, annealing time 1h, sputtering power 300W, annealing atmosphere pure nitrogen and deposition temperature 500K. Sheet resistance, transmittance in visible region and resistivity of the film prepared with above parameters are 17Ω/, 85.13%, 1.87×10-4Ω•cm, respectively.
In this study, four kinds of organic light-emitting diodes were developed using vacuum deposition technique. The typical multilayer structures of OLED are ITO / CuPc(200 Å) / α-NPD(600 Å) / Alq3(400 Å) : C545T(X%) / Alq3(200 Å) /LiF(10 Å) / Al(1000 Å) , X% is the doping consistence in Emitter Layer of OLED. The value is change from 1% to 4%. In this letter, the optical and electronic performance including brightness, efficiency, spectrum etc. was change with the doping consistence. When X% is 1%, the steady voltage of device start working is lower than other structures, only 2.5V. When X% is 3%, the brightness of the device was measured to be 10,500cd times m-2 at the drive voltage 20V, CIE coordinates x=0.331, y=0.625 and maximum luminous efficiency 6.72 lm•W-1 at 5 V. When X% is 4%, the green emission spectrum peak is 550nm, almost reach 555nm (standard green spectrum peak).
Based on modulation transfer function (MTF), a CRT projection tube resolution measurement system has been developed. This system features auto optical focusing and voltage focusing. It has high resolution, fast measuring speed and friendly operation interface. The results indicate that the error of the system is within ±4% by measuring the standard optical slit ranging 30μm to 500μm, while repeatability is better than 95%. Moreover, the measured data demonstrate that the resolution of YAG projection tube can meet the demands of HDTV.
A full color 2.2" passive matrix organic light-emitting diodes (OLEDs) with 128 (RGB) * 160 pixels was developed. The display features that driving circuit can transform 18 bits gray-scale data from a PC to the OLED panel via a DVI channel. The size of the pixel was 240μm×240μm, while that of mono sub-pixel is 190μm×45μm. The lifetime of panel was estimated over 5000h because of the use of dual-scan driving technology, and the power consumption of the display was 300mw about when the average luminance of panel reach 40cd/m2.
A type of chromatic measuring system, which was based on the spectroradiometric method, controlled by a computer was developed. Spectra, chromaticity coordinates and correlated color temperature (CCT) of light-emitting diode (LED) can be real time measured by this system. It has high resolution of wavelength with 0.2nm, fast measuring speed and friendly operation interface. The measurement data indicate that the system has higher accuracy than CS-100. Difference between measured result and standard data of the system is within ± 2%, while repeatability is better than 98%.
A novel 5-in. R.G.B densely packed poly-crystal MgAl2O4 (magnesium-aluminum-oxide) phosphor screens with multi-layer interface filter have been developed. The filter is a multi-layer alternate high and low index of refraction film which was fabricated by depositing high index of refraction of titanium oxide and low index of refraction of silicon oxide. The 5-in.R.G. B densely packed poly-crystal phosphor screens with the filter have 60% more luminance than those of common R.G. B poly-crystal phosphor screens, and the area of their chromaticity is almost 10% larger than that of common poly-crystal phosphor screen. The 5-in.R.G. B densely packed poly-crystal phosphor screens with multi-layer interface filter are fabricated by using a centrifugal sedimentation method. The resolution of densely packed poly-crystal phosphor screen with multi-layer interface filter is higher than that of conventional poly-crystal phosphor screen. An experimental 52-inch TV set adopting the set of 5-inch densely packed poly-crystal projection CRT with multi-layer interface filter has very high resolution of 2000 TV lines and 1800 cd/m2 luminance, and it is easy to realize the HDTV display.
As we know, Strong fluorescent dyes are important light-emitting materials of OLED. 8-hydroxyl quinoline aluminum (Alq3) is one of the best electroluminescent materials with good film-formation and thermal, excellent electron-transporting ability. However Alq3 is mostly employed in OLED device for electron transport layer or host material by vacuum deposition. Because of its poor dissolubility in common organic solvent, and be easily recrystallized from the OLED device, the stability of OLED with Alq3 is decreased. To overcome such defects, we have designed and synthesized five kinds of Alq3 derivatives. Their chemical structures were elucidated by IR, 1HNMR and element analysis. Their photoluminescence (PL) and electroluminescence (EL) properties have been investigated and the relationships between molecular structures and light- emitting properties have been studied as well.
The crosstalk, equivalent circuit, voltage drop and power consumption of passive matrix organic light-emitting diodes (PMOLEDs) are quantitatively analyzed, and a mathematical model to calculate the power of PMOLEDs is built. In particular, the advantages of dual-panel PMOLEDs are discussed. The model demonstrates that the power of dual-panel PMOLEDs can be significantly reduced comparing with that of single-panel PMOLEDs. Two 2.5-in. 128×64-pixel green small molecule PMOLEDs have been fabricated. One is single-panel, and the other dual-panel. The power consumption of dual-panel PMOLEDs is 25% less than that of single-panel when both are operated at an average luminance of 100cd/m2.
A novel transparent organic light emitting diode (TOLED) has been developed. This TOLED features Lanthanum hexaborides (LaB6) as transparent cathode and has the device structures of ITO/TPD/Alq3/LaB6. LaB6 film was prepared by the electrons evaporation. This device has the transparency of ~70% in visible spectra, and reach a luminance of 100cd/m2 at 7.2v corresponding to injected current density of 4.8mA/cm2.
We have ever reported a phosphor screen, which is a 5-in. poly-crystal MgAl2O4 phosphor screen. The 5-in. poly-crystal MgAl2O4 phosphor screen has a very good performance, such as high luminance, high resolution, cheap cost and easily obtained. Recently we develop a high performance 5-in. poly-crystal phosphor screen. We deposit a multi-layer interface filter on the poly-crystal MgAl2O4 substrate. The filter is a multi-layer alternate high and low index of refraction film which was fabricated by depositing high index of refraction of titanium oxide and low index of refraction of silicon oxide. The measurement results show that the filter not only increases the MgAl2O4 phosphor screen’s white-D luminance, but also improves its chromaticity. The 5-in.R.G. B poly-crystal phosphor screens with the filter have 60% more luminance than those of common R.G. B poly-crystal phosphor screens, and the area of their chromaticity is almost 10% larger than that of common poly-crystal phosphor screen. The 5-in.R.G. B poly-crystal phosphor screens with the filter realize the authentic high performance.
Conventionally, small-molecule organic electroluminescent device is fabricated by vacuum depositing technology. In this paper, a novel small-molecule organic electroluminescent device was proposed. We adopt spin-coating technology to fabricate the device. It makes the fabrication of small-molecule organic electroluminescent device very simple and low-cost. The device has a brightness of 100 cd/m2 at the 16V DC drive voltage.