New Class of Light Sensitive Nanoparticle Makes Solar Cells Cheaper and Lighter

The latest development in solar technology is a new class of solar sensitive nanoparticless that could lead to the development of cheaper and more flexible solar cells.

The newly designed and tested solar sensitive nanoparticles called colloidal quantum dots are solid, stable light-sensitive nanoparticle that will help in building cheaper and flexible outdoor solar cells compared to the present ones. Apart from this, the nanoparticles could lead to better gas sensors, infrared lasers, infrared light emitting diodes and much more. 

Developed by post-doctoral researcher Zhijun Ning and Professor Ted Sargent, the tiny   colloidal quantum dots collect sunlight using two types of semiconductors mainly n-type that are rich in electrons and p-type that ares poor in electrons.  But the main problem here is that on exposure to air, n-type materials bind with oxygen atoms and lose their electrons to convert into p-type.

To overcome this challenge the researchers demonstrated a new colloidal quantum dot n-type material that does not bind with oxygen on exposure to air.

By maintaining stable n and p type layers at the same time, the researchers were able to boost the efficiency of absorption of light and this may help in building new optoelectronic devices that take advantage of both light as well as electricity.

"This is a material innovation, that's the first part, and with this new material we can build new device structures," said Ning. "Iodide is almost a perfect ligand for these quantum solar cells with both high efficiency and air stability-no one has shown that before."

When tested, the new hybrid n and p type material achieved 80 percent solar power conversion efficiency. The researchers state that these dots could further be combined into inks and painted or printed on thin, flexible surfaces like roofs, whcih  would reduces cost and accessibility of solar power.

"The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance, or power conversion efficiency," said Sargent. "The field has moved fast, and keeps moving fast, but we need to work toward bringing performance to commercially compelling levels."

The finding was documented in Nature Materials.