Poly(3-hexylthiophene) (P3HT):1-(3-methoxycarbonyl)-propyl-1-Phenyl-(6,6)C-61 (PCBM) photovoltaic devices based on ordinary paper as substrate were fabricated. Au layer deposited on paper by RF magnetron sputtering was used as anode. The hybrid layer of LiF co-evaporated with Al was used for transparent cathode, and the light transmittance could reach to similar to 70%. By optimizing the mass proportion of LiF and Al, we could get the best papery solar cells with the short current density and open circuit voltage 0.1 mA/cm(2) and 0.39 V. respectively. The corresponding power conversion efficiency was measured to be 0.13 parts per thousand illuminated with 100 mW/cm(2) air mass 1.5 global (AM 1.5 G) simulated sunlight. (C) 2010 Elsevier B.V. All rights reserved.

After the premier commercialization of OLED in 1997, OLED has been considered as the candidate for the next generation of flat panel display. In comparison to liquid crystal display (LCD) and plasma display panel (PDP), OLED exhibits promising merits for display, e. g., flexible, printable, micro-buildable and multiple designable. Although many efforts have been made on electroluminescent (EL) materials and devices, obtaining highly efficient and pure blue light is still a great challenge. In order to improve the emission efficiency and purity of the blue emission, a new bipolar blue light emitter, 2,7-di(2,2': 6', 2 `'-terpyridine)- 2,7-diethynyl-9,9-dioctyl-9H-fluorene (TPEF), was designed and synthesized. A blue OLED was obtained with the configuration of ITO/PEDOT/PVK:CBP:TPEF/LiF/Al. The device exhibits a turn-on voltage of 9 V and a maximum brightness of 12 cd/m(2) at 15 V. The device gives a deep blue emission located at 420 nm with the Commission Internationale de l'Eclairage (CIE) coordinates of (0.17, 0.10). We also use TPEF as electron transporting material in the device of ITO/PPV/TPEF/LiF/Al, the turn-on voltage is 3 V. It is proved the current in the device was enhanced indeed by using the new material.

The energy band of red light-emitting materials is usually very narrow, which easily results in non-radiative recombination of excited states. There also exists concentration q(1)uenching effect due to strong pi-pi interaction. To avoid this, host-guest doping system is mostly used. On the other hand, the ratio of singlet and triplet excited state caused by recombination is 1:3. In comparison with the fluorescence (singlet to singlet), phosphorescence (triplet to singlet, but spin-forbidden) is much weaker, and the quantum yield is much lower. To enhance it and make full use of triplet excited state energy, heavy atom effect is commonly used to induce strong spin-orbital coupling leading to mix of singlet and triplet and release the forbidden triplet energy. Based on this, we fabricated polymer light-emitting diodes adopting polyvinylcarbazole (PVK) as the host and a red fluorescent dye, 2-\2-methyl-6-[2-(2,3,6,7-tetrahydro-1H, 5H-pyrido[3,2,1-ij]quinolin-9-yl)-vinyl]-pyran-4-ylidene\-alononitril e (DCM2), as the dopant, and materials containing heavy-ion, kalium idode (KI) and bromo-carbazole, as energy transfer bridge to obtain complete energy transfer from excited states of both singlet and triplet energy level of PVK to ground state of singlet of DCM2. We found the current density of devices with heavy-ion materials were higher than device without it, and the weak blue emission from PVK host, existing in device of PVK:DCM2 device, can not be observed in electroluminescence spectra of device with heavy-ion materials, which indicates a complete energy transfer from both triplet and singlet energy levels.

A facile way to fabricate highly efficient organic light emitting devices (OLEDs) with insulator MnO as an electron injecting and transporting material was devised, which eliminates the problem of the oxidation of reactive dopants. The power efficiency of 1.1 lm/W by inserting 3-nm-thick MnO as the electron injecting layer was obtained, higher than the 0.8 lm/W efficiency for the reference device with 0.5-nm-thick LiF. A thermal co-evaporation layer containing 10% weight of MnO and tris(8-hydroxyquinolato) aluminum (Alq(3)) as the electron transporting layer showed more efficient electron transport ability, with turn-on voltage of 3.8 V, lower than 7.4 V for the intrinsic Alq3. Meanwhile, the insertion of thin MnO layer between organic photoactive layer and inorganic metal electrode significantly improved performance and stability of organic solar cell compared to device without it. The power conversion efficiency (PCE) of 2.91% by inserting 3-nm-thick MnO was obtained, higher than the 0.91% efficiency for the device without it, and 2.59% for the device with 0.5-nm-thick LiF. Charge transport of rhenium trioxide (ReO(3)) in organic electronic devices was investigated. The hole injection/transport was blocked and the electron injection/transport was enhanced with doping of ReO(3) in organic electronic devices. Thus the charge balance and efficiency of the OLED were improved, 2.7 cd/A of current efficiency (CE) at 20 mA/cm(2) for the device with ReO(3) was higher than 1.5 cd/A for the device without it. In the case of organic photovoltaic cells (OPV), the open-circuit voltage (V(oc)), 0.58 V, was higher compared to the device without ReO(3) (0.44 V) due to the improvement of interface properties. The PCE was increased to 2.27% by the combination of ReO(3) (increasing V(oc)) with poly(3,4-ethylene dioxythiophene): poly(styrene-sulfonate) (PEDOT:PSS) (improve hole transport to increase J(sc)) on the modification of the anode, higher than 1.85% for the device without ReO(3).