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Nagwa Ibrahim

Country of origin: Sudan Currently in: Saudi Arabia, Zulfi General field of specialization: Physics
Academic Background


1966 Doctorate Physics
Research and Profession

Current Research Activities

Study on the thickness dependence of the performance of bulk heterojunction solar cells based on poly ( 2-methoxy-5-) 3,7-dimethyloctyloxy) 1,4-phenylenevinylene) MDMO:PPV as an electron donor and (6,6)-phenyl C61 butyric acid methyl ester PCBM as an electron acceptor. The thicknesses of the donor and acceptor (blend) are 25 nm, 40 nm, and 60 nm, and the active surface area of the cell is 1.5 mm 2. All measurements are taken at a temperature of 300 0K. A 0.3 W/m2 lamp is used as a source of light. It has been commonly accepted that increasing the blend thickness beyond 100 nm does not increase the efficiency. The results of this work show that the optimum thickness of the blend is about 40 nm. The efficiency of a MDMO: PPV/PCBM solar cell is found to be 2.8%, at a blend thickness of 40 nm . By lowering the offset of (LUMO) A-(LUMO) D, to be 0.5 eV, the device efficiency would increase to about 8%, showing the great importance of matching the electronic levels of donor and acceptor. Ohmic contact is found to increase the short circuit current, it slightly decreases the open circuit voltage. Experimental show that the voltage losses, which could be due to band bending, equal 0.3 V


Sudan Institute for Natural Sciences

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