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Chemistry: Giant hyperthermal effect in Mg-doped Fe3O4 - Friday, 09 February 2018 11:36
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Ecology: Nano-products risks overexaggerated - Tuesday, 24 June 2014 11:02

nanokorea2013Join the leading nanotechnology event in the Asian region, Nano Korea 2013.

PlasmaChem GmbH is proud to be the sponsor of the event, and attend the exhibition represented by the distributor in Korea iNexus Co. (4science.net) at stand S16. Join the event, receive a brand new edition of nanomaterials catalogue, and get a special discount from PlasmaChem on your purchases in 2013!

More about the event:

Being one of the leading promoters of nanotechnology, PlasmaChem GmbH - the German nanomaterials manufacturer and the worldwide first nanomaterials catalogue company - in frame of the material introduction, offer 20% discount on TiO2 nanowires. The offer is valid until 07 November 2012.

10percent QD-ink solarcells titelA new article by Aqoma et al provides additional inspiration to all those working on the development of flexible low-cost high-performance solar cells.

The authors could achieve 10% conversion efficiency by employing the PbS quantum dots as the absorbing layer. Using CQD-ink, the fabrication of active layers by single-step coating and the suppression of surface trap states are achieved simultaneously. The CQD-ink photovoltaic devices achieve much higher PCEs (10.15% with a certified PCE of 9.61%) than the control devices (7.85%) owing to improved charge drift and diffusion.

This article provides new perspectives for the development of new generation of solar cells.

 

More information available in the Advanced Materials´High-Efficiency Photovoltaic Devices using Trap-Controlled Quantum-Dot Ink prepared via Phase-Transfer Exchange

 

 

 

PbSCdS solar cell 6percent

The highly potential solar cell technology based on colloidal quantum dots (CQD), still has to overcome several problems in order to climb above the competing technologies. One of such bottlenecks is the lower than predicted open-circuit voltage due to the defects in the lattice of the QDs.

The recent work from the group of Prof. Watt (Oxford University) published in ACS’s journal Chemistry of Materials, suggests an approach to increase the voltage without a negative impact on the current. “This is done by developing a passivation strategy that uses the synergistic effect of a core/shell structure and ligands coordination to passivate CQD surfaces” tells the first author Dr. Neo.

Contrary to the sophisticated techniques of building up a solar cell, the authors decided to utilize the technology, which has an easy and cheap potential for scale-up, namely spin-coating from solutions.

Using this method, they assembled the solar cells from PEDOT:PSS, QDs and ZnO layers sandwiching them between aluminium and ITO electrodes. The core of the work was to study the influence of the QDs structure on the cell efficiency.

QD-based-laser-2013Quantum Dots Laser Developed

In a search for a more reliable and tuneable laser sources, a group of scientists led by Prof. Lee from the National Cheng Kung University of Taiwan developed a quantum-dots based laser. Colloidal quantum dots (QD) of CdSe/ZnS were embedded into a cholesteric liquid crystal matrix. The article is soon to be published in Advanced Optical Materials.

Liquid crystals, which have photonic crystal behaviour, are already used in construction of dye-doped lasers, which, however, have several drawbacks such as thermal, chemical and photo- instabilities. 

This study was the first to report a highly directional lasing emission based on a QD-embedded CLC (QDCLC) cell. Experimental results showed that the QDs had a key function not only as the nanoscaled source of fluorescence emission but also as the structural stabilizer of the CLC microresonator. 

Comparing the developed QD-laser with the existing dye-doped laser, Prof. Lee said,  "The developed QDCLC laser could tolerate a strong pumped energy without damage (over 83 μ J/pulse), and this threshold is over 1.66 times higher than that (50 μ J/pulse) of a traditional DDCLC laser. The divergence angle of the QDCLC lasing emission is 1.67 times smaller than that of the DDCLC lasing emission. Furthermore, the QDCLC laser has flexibly thermal and electrical tunabilities in the lasing threshold, linewidth, and wavelength." 

"Combining the QD gain medium and the tunable CLC resonator can potentially result in the fabrication of tunable coherent light sources or laser devices (e.g., tunable single photon laser) with advantages of low cost, highly fl exible tunability, high stability, high damage threshold, lower beam divergence, and high reusability" Prof. Lee said.

All of the materials used in this study including CdSe/ZnS quantum dots are commercially available.

Related articles:
QDs Plus MOF for enhanced Light-Harvesting
Quantum Dots Can Shine Even Brighter

NanoJam (C) 2013
Image Source: John Wiley & Sons, Inc

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