Synthesis And Study Of New Type Organic Solar Cells

With the constant demand of clean energy and the decrease of fossil oil, it is urgent to develop a new kind of clean energy to meet the need of the new era. Organic solar cells(OSCs) have drawn great attention from the scientific research community, due to its low processing cost, light weight, mechanical flexibility and environmental friendly. The performance of OSCs can be enhanced by several solutions including the application of high efficient narrow band gap functional materials, morphology control of the active layers, additives, optimal device configuration and interfacial engineering. Interfacial engineering has developed for decades, and it is widely used in promoting the power conversion efficiency of OSCs. The effect of using interlayer is obvious good and functional materials are also involved in this paper. In this paper, the vanadium or bismuth doped molybdenum oxide as anode interface materialsand the application of two kinds of new Donor-Accepter(D/A) copolymers as donor in OSCswere studied. The main content of this paper is as follows:1.P-type molybdenum oxide made by ammonium molybdate((NH4)6Mo7O24) and ammonium metavanadate( NH4VO3)was inserted as anode interlayer between ITO anode electrode and the active layer in organic solar cells with Li F as cathode interlayer and Al as cathode electrode. The work function of the p-type molybdenum oxide coated on ITO was measured by Kelvin probe and the device performances with different doping ratios and thicknesses were also studied. The devices with p-type molybdenum oxide exhibited a power conversion efficiency of 4.32% under 100mW/cm2AM1.5 illumination compared with which use PEDOT: PSS as anode interlayer with the power conversion efficiency of 3.19%. The performance improvement was attributed to that the p-type molybdenum oxide thin film can module Schottky barrier and form an ohmic contact at the organic/metal interface and enhance hole mobility,which makes it an alternative candidate for effective hole-transporting material.2. Another p-type compound made by ammonium molybdate((NH4)6Mo7O24) and bismuth nitrate(BiNO3)3 was prepared via sol-gel methods and then was introduced as anode interlayer in P3HT: PCBM devices. The devices with p-type molybdenum oxide exhibited a power conversion efficiency of 4.22% under 100mW/cm2AM1.5 illumination.And through the IPCE,AFM,SCLC,XPS,work function and UV-vis testing, we can draw a conclusion that the devices improvement can be attributed to the better morphology and the high transmittance. Theopen circuit voltageisincreased by the insert of the interface materials,indicating that bismuth oxides may be a candidate in OSCs as anode interlayer.3. Two novel D-A-type conjugated polymers bearing PPz unit of PTTPPz-BDT and PTTPPz-BDTT were prepared and characterized. The effects of thermal annealing and donor/acceptor ratios on the performance of the OSCs were studied. The highest PCE of 4.86% was obtained in the optimized PTTPPz-BDTT/PC71 BM device with Jsc of 11.10 mAcm-2, Voc of 0.70 V and FF of 62.5%. The results demonstrated that incorporating large planar PPz moiety into the D-A-type copolymer is an efficient strategy to improve the absorption, mobility and thus photovoltaic performance of the copolymers. The importance of promoting the properties of functional materials is also apparent.