Exploiting metallophilicity for the assembly of inorganic nanocrystals and conjugated organic molecules

The accurate engineering of interfaces between inorganic nanocrystals and semiconducting organic molecules is currently viewed as key for further developments in critical fields such as photovoltaics and photocatalysis. In this work, a new and unconventional source of interface interaction based on metal–metal bonds is presented. With this aim, an AuI organometallic gelator was exploited for the formation of hydrogel-like nanocomposites containing inorganic nanoparticles and conjugated organic molecules. Noteworthy, the establishment of metallophilic interactions at the interface between the two moieties greatly enhances interparticle coupling in the composites. Thus, we believe that this new hybrid system might represent a promising alternative in several fields, such as in the fabrication of improved light-harvesting devices.Peer ReviewedPostprint (author's final draft

Direct electrical evidence of plasmonic near-field enhancement in small molecule organic solar cells

We present a simple and versatile technique to introduce plasmonic silver nanoparticles into organic thin film devices by in situ vacuum deposition. Silver particles with 80 nm diameter at the back of small molecule organic solar cells increase the power conversion efficiency (PCE). Doped organic transport layers allow one to separate electrical and optical effects. By a systematic variation of the position of the silver particles within the solar cell stack, we can thus clearly distinguish a near-field photocurrent gain in the IR that decays to one-half on length scales of around 4 nm, and a less distance-dependent selective mirror effect for short wavelength, which allows one to optimize devices for different wavelengths simultaneously. Device optimization reveals that plasmonic increased absorption can be used to significantly reduce the thickness of the absorber layers and gain efficiency through improved transport properties. A plasmonic zinc phthalocyanine fullerene-C60 solar cell that yields improved photocurrent, fill factor, and PCE of 2.6% includes one-half of the absorber material of an optimized reference device with PCE of 2.4%. The design priciples for plasmonic solar cells are general and were confirmed in thin devices containing zinc 1,8,15,22-tetrafluoro-phthalocyanine, improving the PCE from 2.7% to 3.4%. © 2014 American Chemical Society

Direct electrical evidence of plasmonic near-field enhancement in small molecule organic solar cells

We present a simple and versatile technique to introduce plasmonic silver nanoparticles into organic thin film devices by in situ vacuum deposition. Silver particles with 80 nm diameter at the back of small molecule organic solar cells increase the power conversion efficiency (PCE). Doped organic transport layers allow one to separate electrical and optical effects. By a systematic variation of the position of the silver particles within the solar cell stack, we can thus clearly distinguish a near-field photocurrent gain in the IR that decays to one-half on length scales of around 4 nm, and a less distance-dependent selective mirror effect for short wavelength, which allows one to optimize devices for different wavelengths simultaneously. Device optimization reveals that plasmonic increased absorption can be used to significantly reduce the thickness of the absorber layers and gain efficiency through improved transport properties. A plasmonic zinc phthalocyanine fullerene-C60 solar cell that yields improved photocurrent, fill factor, and PCE of 2.6% includes one-half of the absorber material of an optimized reference device with PCE of 2.4%. The design priciples for plasmonic solar cells are general and were confirmed in thin devices containing zinc 1,8,15,22-tetrafluoro-phthalocyanine, improving the PCE from 2.7% to 3.4%. © 2014 American Chemical Society

Plasmonic Shaping in Gold Nanoparticle Three-Dimensional Assemblies

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