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We evaluate practical power conversion efficiency limits ͑␩ lim ͒ in bulk-heterojunction organic photovoltaic ͑BHJ OPV͒ cells and how the field dependence of exciton dissociation affects cell efficiencies. We treat the fill factor limit as a function of the donor-acceptor lowest unoccupied molecular orbital offset energy ͑E LLO ͒, calculating how this limit(More)
Universality of non-Ohmic shunt leakage in thin-film solar cells" We compare the dark current-voltage ͑IV͒ characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon ͑a-Si:H͒ p-in cells, organic bulk heterojunction ͑BHJ͒ cells, and Cu͑In, Ga͒Se 2 ͑CIGS͒ cells. All three device types exhibit a significant shunt leakage(More)
Traditional inorganic solar cell models, originating with the work of Shockley, are widely used in understanding bulk heterojunction (BHJ) organic solar cell response (organic solar cells are also referred to as organic photovoltaics, or OPVs). While these models can be useful, there are several key points of departure from traditional solar cell behavior.(More)
In studies to simplify the fabrication of bulk-heterojunction organic photovoltaic (OPV) devices, it was found that when glass/tin-doped indium oxide (ITO) substrates are treated with dilute aqueous HCl solutions, followed by UV ozone (UVO), and then used to fabricate devices of the structure glass/ITO/P3HT:PCBM/LiF/Al, device performance is greatly(More)
Modeling of organic photovoltaic (OPV) cells can be achieved by adaptation of drift-diffusion models. Replacement of traditional crystalline solid state materials by organic materials leads to much lower carrier mobility and to a new carrier, the exciton, which is a bound electron-hole pair. The Buxton-Clarke model includes electrons, holes, and excitons,(More)
Highly conductive In-doped CdO/Sn-doped In 2 O 3 (CIO/ITO) bilayer transparent conducting oxide (TCO) thin films were prepared by combining, in sequence, metal-organic chemical vapor deposition (MOCVD) and ion-assisted deposition (IAD) techniques. The bilayer substrates, with a low In content of ∼19 atom % and a low sheet resistance of only ∼4.9 Ω/0, were(More)
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