We report on a modified bulk heterojunction (BHJ) solar cell in which a nanohybridized composition of lead sulfide (PbS) colloidal quantum dots (QDs) and multiwall carbon nanotubes (MWCNTs) were incorporated into a standard regioregular poly(3-hexylthiophene) (rr-P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blend. This hybrid ((P3HT:PCBM):PbS-QD/MWCNT) solar cell exhibits an increased power conversion efficiency (PCE) of 3.40% as compared to that of 2.57% from a controlled P3HT:PCBM standard BHJ solar cell fabricated under similar experimental conditions. The 32% increase in efficiency is effectively attributed to the extended quantum-dot-sensitization in the near-infrared (NIR) due to the absorbance of QDs/CNTs in the spectral range from 700 nm to 1450 nm. The strong conjugation, controlled coupling and nanohybridization of QDs/CNTs played an important role towards the improvement of PCE since it is proposed that excitons generated in the QDs can be efficiently dissociated at the QD/CNT interface by transferring the electrons to the CNTs followed by holes transfer to the P3HT. In this ternary blend, the staggered energy band alignment between P3HT and the QDs allows both electrons and holes transfer from the QDs to the PCBM and the P3HT, respectively. Subsequently, the dissociated carriers have been efficiently transported by the CNTs and P3HT to favorable respective electrodes.

We report the first disposable fluorescent biosensor based on algae, with an organic light emitting diode and an organic photodetector (OPD) miniaturized into a microfluidic chip. A DPVBi OLED was used as the excitation source, while a blend of PTB3/PCBM was used for the organic photodetector. The fluorescence biosensor is integrated in a microfluidic chip made from polymeric materials such as (poly)dimethylsiloxane (PDMS), which is transparent, biocompatible and can easily be processed by conventional lithography. The complete detector is designed to detect Chlamydomonas reinhardtii green algae fluorescence in the microfluidic chamber. Algal chlorophyll fluorescence is a physiological parameter routinely used to measure the photochemical efficiency of PSII. This measurement is a reliable and non-invasive method to determine the toxicity of pollutants like herbicides and metals.

Electrical bistability is reported in metal-organic-metal diodes. The device consists of two Al electrodes separated by an organic layer that contains embedded Au nanoparticles (NPs) supported by parylene nanopillars. This paper presents results with two different organic materials: 2-amino-4, 5-imidazoledicarbonitrile (AIDCN) and aluminum tris(8-hydroxyquinoline) (Alq3). Electrical characterization of the diodes shows bistability with two well-defined states with high (OFF) and low (ON) resistances. The ON/OFF ratio is 104 and current-voltage (I-V) curves show a negative differential resistance (NDR). The diodes can be programmed in either the ON or the OFF state and maintained it for at least 8 months in air without any evidence of degradation. This conspicuous memory effect is rationalized in terms of charge storage mediated by the oxidation/reduction of the NPs. The fabrication method is general and provides a good control on both the size-uniformity and the position of the Au NPs embedded in the organic materials. The diode characteristics with different NP density are also addressed.

We have developed a simple, compact and economical diode laser-assisted process for the direct writing of gold and copper on polyimide. Gold precursor films were deposited by spin-coating a commercially available organometallic compound onto the substrate. The local pyrolysis of these films was induced by the focused beam of an AlGaAs diode laser array ( Pmax = 1 W, λ = 796 nm). Direct writing was achieved in open air while moving the substrate at speeds up to 15 mm/s. Gold lines 13–17 μm wide, ∼0.1 μm thick, and having a resistivity of 30 μΩ·cm, were obtained on polyimide with good reproducibility using writing speeds > 10 mm/s. Following a simple annealing process, these gold lines successfully activated the electroless plating of copper. After 45 min of plating, 2 μm thick Cu/Au conductors, having a resistivity of 8 μΩ·cm, were deposited. A commercially available copper precursor was also studied for the direct deposition of copper.