Improving the Photostability of Small-Molecule-Based Organic Photovoltaics by Providing a Charge Percolation Pathway of Crystalline Conjugated Polymer.

Photostability of small-molecule (SM)-based organic photovoltaics (SM-OPVs) is greatly improved by utilizing a ternary photo-active layer incorporating a small amount of a conjugated polymer (CP). Semi-crystalline poly[(2,5-bis(2-hexyldecyloxy)phenylene)--(5,6-difluoro-4,7-di(thiophen-2-yl)benzo[][1,2,5]thiadiazole)] (PPDT2FBT) and amorphous poly[(2,5-bis(2-decyltetradecyloxy)phenylene)--(5,6-dicyano-4,7-di(thiophen-2-yl)benzo[][1,2,5]thiadiazole)] (PPDT2CNBT) with similar chemical structures were used for preparing SM:fullerene:CP ternary photo-active layers. The power conversion efficiency (PCE) of the ternary device with PPDT2FBT (Ternary-F) was higher than those of the ternary device with PPDT2CNBT (Ternary-CN) and a binary SM-OPV device (Binary) by 15% and 17%, respectively.

Reducing Trap-Assisted Recombination in Small Organic Molecule-Based Photovoltaics by the Addition of a Conjugated Block Copolymer.

The performance of organic photovoltaics (OPVs) based on the small-molecule organic semiconductor p-DTS(FBTTh ) is greatly improved by the addition of a conjugated block copolymer composed of difluoroquinoxaline and thienopyrrolodione blocks (D130). The power conversion efficiency (PCE) of the p-DTS(FBTTh ) -based OPV is improved from 5.08% to 6.

Trap-free transport in ordered and disordered TiO2 nanostructures.

Understanding the influence of different film structures on electron diffusion in nanoporous metal oxide films has been challenging. Because of the rate-limiting role that traps play in controlling the transport properties, the structural effects of different film architectures are largely obscured or reduced. We describe a general approach to probe the impact of structural order and disorder on the charge-carrier dynamics without the interference of transport-limiting traps.

Voltage-enhancement mechanisms of an organic dye in high open-circuit voltage solid-state dye-sensitized solar cells.

Sensitization of solid-state dye-sensitized solar cells (SSDSSCs) with a new, organic donor-π-acceptor dye with a large molar absorption coefficient led to an open-circuit voltage of over 1 V at AM1.5 solar irradiance (100 mW/cm(2)). Recombination of electrons in the TiO(2) film with the oxidized species in the hole-transfer material (HTM) was significantly slower with the organic dye than with a standard ruthenium complex dye.

Effect of coadsorbent on the photovoltaic performance of zinc pthalocyanine-sensitized solar cells.

The effect of chenodeoxycholic acid as a coadsorbent on TiO 2 nanocrystalline solar cells incorporating phthalocyanine sensitizers was studied under various conditions. Adding chenodeoxycholic acid onto TiO 2 nanoparticles not only reduces the adsorption of phthalocyanine sensitizers but also prevents sensitizer aggregation, leading to different photovoltaic performance. The inspection of IPCE and absorption spectra showed that the load of phthalocyanine sensitizers is strongly dependent on the molar concentration of chenodeoxycholic acid coadsorbent.

Efficient co-sensitization of nanocrystalline TiO(2) films by organic sensitizers.

Dye-sensitized solar cells based on co-sensitization of organic dyes having complementary spectral absorption in the visible region resulted in a panchromatic response, which exhibited 86% incident monochromatic photon-to-current conversion efficiency in the visible region; the optimized cell gave a short circuit current density of 15.5 mA cm(-2), an open circuit voltage of 685 mV and a fill factor of 0.70 corresponding to an overall conversion efficiency of 7.

Linkage of N3 dye to N3 dye on nanocrystalline TiO2 through trans-1,2-bis(4-pyridyl)ethylene for enhancement of photocurrent of dye-sensitized solar cells.

Linking of N3 dye to another TiO2-attached N3 dye rendered an enhanced short-circuit photocurrent and thereby higher efficiency for the dye-sensitized solar cell with the pertinent TiO2 film electrode.

Incorporation of functionalized single-wall carbon nanotubes in dye-sensitized TiO2 solar cells.

Effects of incorporation of acid-treated single-wall carbon nanotubes (a-SWCNs) in TiO(2) film and of anchorage of dye-linked, a-SWCNs (hereafter dye-SWCNs) to the TiO(2)/electrolyte interface on photocurrent-voltage characteristics of dye-sensitized solar cells were studied. Compared with an unmodified cell, the modified cell with the a-SWCNs in TiO(2) film showed a 25% increase in short-circuit photocurrent (J(sc)). The J(sc) increase is correlated with improved connectivity between the a-SWCNs and the TiO(2) particles and with enhanced light scattering by TiO(2) clusters formed in the presence of the a-SWCNs.