We investigate the effects of interfacial layers on the photovoltaic properties of bilayer organic heterojunction photovoltaic devices. The devices were fabricated using aluminum phthalocyanine chloride (AlPcCl) as electron donor and fullerene (C60) as electron acceptor. Two types of interfacial layers inserted between the transparent indium-tin-oxide anode and the AlPcCl layer were investigated: PEDOT:PSS and MoO3. We find that these interfacial layers have a strong influence on the device open-circuit voltage (VOC). The effects of temperature and illumination intensity on VOC were explored.
We investigate the dependence of the photovoltaic characteristics of organic photocells on the relative concentration of the donor-acceptor molecular complex. The devices were fabricated using a new [MEH-PPV] - co - [phenylene vinylene] blend with C60. We find that the morphology and device performance are strongly influenced by the molar fraction (x) of C60 in the electroactive layer of the device. The best device was obtained with x = 0.6 and manifested VOC = 0.85 V, JSC = 2.65 mA/cm2, FF = 0.42, and ηPext = 1%.
Light-emitting diodes (LED5) based on organic semiconductors have received much attention recently due to their promise as cheap, novel light sources for electro-optical applications. Unlike conventional diodes, light emission from these organic LEDs is achieved by double injection of electrons from a low-work-function electrode and holes from a high-work-function electrode into the organic polymer light-emitting layer. By appropriately engineering the polymer backbone, emission of various visible colors has been demonstrated. Our work in this field has concentrated on organic block copolymers as the active light-emitting materials. We demonstrate that the use of copolymer systems leads to large enhancement of device performance.