Showing posts with label nano particle. Show all posts
Showing posts with label nano particle. Show all posts

'Solar Paint' That Generates Electricity !

Green homeowners can now bid goodbye to unwieldy solar panels! An inexpensive "solar paint" has been developed by the researchers at the University of Notre Dame in the US, which can be applied on the outside walls of a house to generate electricity from sunlight. The electricity thus produced by "Sun-Believable Solar Paint" can be used to power the home appliances and equipment on the inside, claim researchers.

"By making use of recent advances in semiconductor nanocrystal research, we have now developed a one-coat solar paint for designing quantum dot solar cells," said Prashant V. Kamat of the Radiation Laboratory and Department of Chemistry and Biochemistry at the University of Notre Dame in Indiana, one of the lead authors of the study. 


"By incorporating power-producing nanoparticles, called quantum dots, into a spreadable compound, we've made a one-coat solar paint that can be applied to any conductive surface without special equipment," Kamat added. 


Talking about the quantum dots in detail, he said these are "semiconductor nanocrystals which exhibit size-dependent optical and electronic properties. In a quantum dot sensitised solar cell, the excitation of semiconductor quantum dot or semiconductor nanocrystal is followed by electron injection into TiO2 nanoparticles. These electrons are then transferred to the collecting electrode surface to generate photocurrent. The holes that remain in the semiconductor quantum dot are removed by a hole conductor or redox couple and are transported to a counter electrode."

Due to its amazing properties, Kamat and his co-workers christened the new paint as "Sun-Believable Solar Paint". If perfected, the new product is sure to herald a new era in solar power. 

Unfortunately, the paint isn't ready for commercial use yet. At around 1 per cent, its efficiency is much less than traditional solar cells. "The best light-to-energy conversion efficiency we've reached so far is 1 per cent, which is well behind the usual 10 to 15 per cent efficiency of commercial silicon solar cells. But this paint can be made cheaply and in large quantities. If we can improve the efficiency somewhat, we may be able to make a real difference in meeting energy needs in the future," Kamat said.  

Nano-Ear That Can Hear Sound Of Bacteria

Scientists at Ludwig-Maximilians University, Munich have created a nano-ear which can trap sound waves much below the human ear can hear. With this technology, scientists have added an entirely new dimension to the domains of acoustics and biology. This nano-ear studies sound waves emitted by micro-organisms.

A team of German engineers including Jochen Feldmann and Andrey Lutich have achieved the breakthrough. After working on the principle of sensing sound waves at nano level, the two scientists have come to the conclusion that if gold nano particles are used along with lasers, an instrument which has sensitivity 6 magnitudes less than human ears can be created. 





The duo used a beam of laser at specific point in this experiment. They created an electric field with the network of lasers. According to a report, this makes the electric dipole moment attract nearest nano particle in the Web so created. 

The frequency of the sound waves making vibrations in nano-particles is sensed and related to sound waves of a particular frequency. The engineers claim that with this nano-ear, one can hear sense sound as low as -60dB.