An artist's illustration ofquantum dots emitting light. Researchers developed a method to more accurately measure the efficiency of quantum dots. The effort hopes to remove any doubts over the performance of quantum dots and make them cheaper alternatives to single crystal semiconductors. ( Ella Marushchenko | Stanford University )
A new study from researchers at Stanford University could pave the way for cheaper semiconductors with near-perfect performances.
The team developed a measurement technique to evaluate the efficiency of quantum dots and demonstrate that the tiny particles could compete with more expensive single-crystal semiconductors. This technique could also remove any long-standing doubts about the particles' quality.
The study was published in Science.
Measuring Quantum Dots Performance
The particles have already broken into the commercial market through quantum dot television, but the potential for defects has been a major deterrent for the semiconductor to be picked up and used in other electronic devices. Because they are smaller, more quantum dots are needed to do the work of a single crystal, opening it up to a bigger possibility of failure.
Techniques that measure the quality of traditional semiconductors found that quantum dots emit over 99 percent of light, but that has not convinced manufacturers to give the tiny particles a chance.
For the study, the researchers developed a measurement technique to better evaluate the quality of quantum dots. It involves analyzing the excess heat produced by energized quantum dots.
According to the researchers, excess heat is a sign of inefficient emission of light.
They found that quantum dots reliably emitted about 99.6 percent of the light they absorbed, which means they are just as efficient as single crystals. The potential error, the researchers reported, was 0.2 percent.
The study claims that the technique is 100 times more precise than the measuring methods used to assess the performance of semiconductors in the past.
"We want to measure emission efficiencies in the realm of 99.9 to 99.999 percent because, if semiconductors are able to reemit as light every photon they absorb, you can do really fun science and make devices that haven't existed before," said David Hanifi, a co-lead author of the study.
Quantum Dot Electronics
The researchers said that their work is not done yet. They hope to continue improving the technique to develop a more precise method to measure the efficiency of semiconductors.
If quantum dots reach 99.999 percent efficiency or above, the particles could lead to the creation of new technologies that were not possible before, such as new glowing dyes that can enhance the ability to look at biology at the atomic scale, or luminescent cooling and luminescent solar concentrators, which allow a small set of solar cells to absorb energy from a large area of solar radiation.
The study is part of a larger effort at the Energy Frontier Research Center, which aims to create optical materials with "the highest possible efficiencies."