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Highly conductive poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is used as an anode material to construct flexible organic photovoltaics on plastic, poly(ethylene naphthalate) (PEN) substrates with a device structure of PEN/modified PEDOT:PSS/poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM)/Al. The indium tin oxide (ITO)-free flexible device exhibits a 20% increase in power conversion efficiency under 1 sun with a higher open circuit voltage (0.67 V) compared to that of the reference device having an ITO anode on a glass substrate (0.54 V). A study of the different recombination mechanisms within these two device structures is carried out by comparing the illumination responses of open circuit voltage as well as short circuit current. The results explain the varying trend of fill factor and power conversion efficiency with respect to the light intensity and suggest that a bimolecular recombination mechanism is dominant in the ITO-free devices. [ABSTRACT FROM AUTHOR]

We introduce a new architecture for organic photovoltaics based on vertically orientated devices. The fabrication, device characteristics, and an optical model of the stack organic photovoltaic (OPV) device are presented. This new architecture gives rise to an alternative to the common flat-panel structure, which was originally conceived for the first silicon devices. The OPV stack device has an increased short circuit current density, fill factor, and power-conversion efficiency, as opposed to the standard flat-panel device. [ABSTRACT FROM AUTHOR]

Abstract: The use of carbon nanotube-fullerene hybrid additives to the standard P3HT:PCBM blend bulk-heterojunction organic photovoltaic device is presented. The effects of incorporating single-wall carbon nanotubes, functionalized with linked C60 molecules by amination on device characteristics are detailed. The concentration of the carbon nanotube-fullerene hybrid in the active layer blend was varied to ascertain their cumulative impact on device performance in terms of open circuit voltage, short circuit current, fill factor and efficiency. We found that decreasing the length of the carbon nanotubes to ∼60nm through fluorination and subsequent thermal treatment was beneficial in terms of eliminating shorted devices allowing much improved diode formation. A trend of improving device performance as a function of concentration of the carbon nanotube-hybrids in a heterojunction of P3HT:PCBM was observed. [Copyright &y& Elsevier]

Electrochemically crosslinked surface-grafted poly(N-vinylcarbazole) (PVK) brushes as hole transport layers (HTLs) on a photovoltaic device have been demonstrated using SI-RAFT polymerization. Comparable performance to PEDOT:PSS/P3HT:PCBM based devices was achieved. A main advantage is strong adhesion to ITO with a possible long-term stability against acid dopants and oxygen. [ABSTRACT FROM AUTHOR]

Organic solar cells show great promise as an economically and environmentally friendly technology to utilize solar energy because of their simple fabrication processes and minimal material usage. However, new innovations and breakthroughs are needed for organic solar cell technology to become competitive in the future. This article reviews research efforts and accomplishments focusing on three issues: power conversion efficiency, device stability and processability for mass production, followed by an outlook for optimizing OSC performance through device engineering and new architecture designs to realize next generation organic solar cells. [ABSTRACT FROM AUTHOR]

Highlights: [•] Solar cells with PPy:PSS have performance as with PEDOT:PSS. [•] PPy:PSS does not etch ITO since there is no PSSH, opposite to PEDOT:PSS. [•] PPy:PSS offers the opportunity for longer-life devices than PEDOT:PSS. [•] Electrodepositing PPy:PSS easy/precise control of film thickness/device performance. [•] PPy:PSS electrodeposited using general electrical equipment no investments required. [ABSTRACT FROM AUTHOR]

Abstract: We have prepared p–n junction organic photovoltaic cells using an all solution processing method with poly(3-hexylthiophene) (P3HT) as the donor and phenyl-C61-butyric acid methyl ester (PCBM) as the acceptor. Interdigitated donor/acceptor interface morphology was observed in the device processed with the lowest boiling point solvent for PCBM used in this study. The influences of different solvents on donor/acceptor morphology and respective device performance were investigated simultaneously. The best device obtained had characteristically rough interface morphology with a peak to valley value ∼15nm. The device displayed a power conversion efficiency of 1.78%, an open circuit voltage (V oc) 0.44V, a short circuit current density (J sc) 9.4mA/cm2 and a fill factor 43%. [Copyright &y& Elsevier]