Light-emitting diodes (LEDs) are prevalent in everything from digital clocks to solar panels, traffic lights, electronic banners and signs, Christmas decorations, as well as smartphone and tablet displays. However, LEDs are created using organic materials that can be costly for researchers. The end result of the manufacturing process is that LEDs cost more for the consumer. While LED lighting systems last longer, are more energy-efficient, and provide an improved color gamut above that of fluorescent lights, the price is the technology’s greatest drawback.
A new, cost-effective quantum dot (QD) hybrid LED could enable LED lighting system adoption on a mass scale. University of Hiroshima (Japan) researchers created the new light-emitting diode using silicon quantum dot solution and a polymer solution on top of an indium-tin-oxide (ITO) glass ply that was used as the anode for the LED. The silicon quantum dot solution was placed in the bottom of a glass vial that sat on a rotating stage. It was synthesized through pulsed laser ablation (PLA) with Tokyo Chemical Industry Co.’s 1-octyne solution (10mL) over several eight-hour periods.
After the 1-octyne solution was removed and the silicon quantum dots solidified, they were then submerged in either 1) 2-propanol or 2) o-dichlorobenzene. “The color of Si QD solution is a transparent yellow but a white-blue PL is observed during the UV excitation,” the team wrote in its report.
The study is the first of its kind to produce silicon quantum dot LEDs by way of a solution-based process and marks an advancement of LED technology, seeing that the use of organic film as the electron transport in past LED production resulted in a decreased photoluminescence and an inaccurate color reproduction. The solution-based process described here was done at room temperature and pressure, resulting in a more cost-efficient process by which to manufacture LEDs. Fluorescent bulbs are cheaper than LEDs, with a box of fluorescent bulbs costing no more than a few dollars, but consume more energy and lead to higher energy bills. LEDs are more expensive up-front, with some costing as high as $70 a piece, but conserve energy and money later on.
Excerpt from extremetech