Improving the efficiency of organic solar cells (OSCs), which are far less efficient than inorganic semiconductor solar cells, is of paramount importance to the field of polymer photovoltaics. Current state-of-the-art bulk heterojunction (BHJ) OSCs utilize a homogeneous blend of the semiconducting polymer poly(3-hexylthiophene) (P3HT) and the fullerene derivative [6,6]-phenyl C61butyric acid me...

We succeeded to fabricate p-n heterojunction and bulkheterojunction small-molecular-weight organic thin-film solar cells by combination of dry (p-type = zinc phthalocyanine, n-type = fullerene) and wet (p-type = tetra-tert-butyl zinc phthalocyanine, n-type = [6,6]-phenylC61-buteric acid methyl ester) processes. Relationship between morphologies of semiconducting layers and photovoltaic properti...

We examine the ultrafast dynamics of exciton migration and polaron production in sequentially processed 'quasi-bilayer' and preblended 'bulk heterojunction' (BHJ) solar cells based on conjugated polymer films that contain the same total amount of fullerene. We find that even though the polaron yields are similar, the dynamics of polaron production are significantly slower in quasi-bilayers than...

Small molecules, namely, DCAO(3)TBDT and DR(3)TBDT, with 2-ethylhexoxy substituted BDT as the central building block and octyl cyanoacetate and 3-ethylrhodanine as different terminal units with the same linkage of dioctyltertthiophene, have been designed and synthesized. The photovoltaic properties of these two molecules as donors and fullerene derivatives as the acceptors in bulk heterojunctio...

There has been much controversy over the incorporation of organic-ligand-encapsulated plasmonic nanoparticles in the active layer of bulk heterojunction organic solar cells, where both enhancement and detraction in performance have been reported. Here through comprehensive transient optical spectroscopy and electrical characterization, we demonstrate evidence of traps responsible for performanc...

To enhance the power conversion efficiency in organic solar cells, charge recombination loss needs to be minimized. First, we perform transient absorption spectroscopy to study the charge recombination dynamics of thin film bulk heterojunction of the archetype organic solar cell molecules, copper phthalocyanine (CuPC) and 3,4,9,10-perylenetetracarboxylic bis-benzimidazole (PTCBI). We report the...

The performance of organic solar cells is determined by the delicate, meticulously optimized bulk-heterojunction microstructure, which consists of finely mixed and relatively separated donor/acceptor regions. Here we demonstrate an abnormal strong burn-in degradation in highly efficient polymer solar cells caused by spinodal demixing of the donor and acceptor phases, which dramatically reduces ...

We have developed a numerical device model that consistently describes the current-voltage characteristics of polymer:fullerene bulk heterojunction solar cells. Bimolecular recombination and a temperatureand fielddependent generation mechanism of free charges are incorporated. It is demonstrated that in poly 2-methoxy53 ,7 -dimethyloctyloxy -p-phenylene vinylene OC1C10-PPVand 6,6 -phenyl C61-bu...

Solution-processed inverted bulk heterojunction (BHJ) solar cells have gained much more attention during the last decade, because of their significantly better environmental stability compared to the normal architecture BHJ solar cells. Transparent metal oxides (MeOx) play an important role as the dominant class for solution-processed interface materials in this development, due to their excell...

We investigate the influence of the energy levels on the power conversion efficiency of a P3HT:PCBM and a MEH-PPV:PV bulk heterojunction cell. We calculate the upper-limit for the efficiency, and make realistic assumptions to predict efficiencies obtainable in the near future. The ideal position of the energy levels of donor and acceptor are obtained from these calculations, giving an idea how ...