LEDs have been hailed as the most environmentally-friendly light source money can buy. They don’t waste heat, last for decades, and use a fraction of the energy required by incandescent bulbs. Yet, LEDs have a dark side. A study published in late 2010 in the journal Environmental Science and Technology found that LEDs contain lead, arsenic and a dozen other potentially dangerous substances.
Thankfully, scientists at the Karlsruhe Institute of Technology and University of Toronto/Canada recently succeeded in manufacturing silicon-based light-emitting diodes (SiLEDs). These next-gen LEDs still emit the same bright, energy-efficient light but are free of heavy metals, making them safer for us and the environment.
In a study published recently in the journal Nano Letters, the international team of chemists, materials researchers, nanoscientists, and opto-electronic experts point out that while silicon has long been thought unsuitable for LEDs, they are capable of producing light at the nanoscopic level.
The SiLEDs produced by the team are highly-efficient, and not limited to the red visible spectral range and the near infrared as past attempts have been. The SiLEDs also have the advantage that they do not contain any heavy metals. In contrast to cadmium selenide, cadmium sulfide or lead sulfide used by other groups of researchers, the silicon used by this group for the light-emitting nanoparticles is not toxic. Moreover, it is available at low costs and highly abundant on earth.
This development could help speed the development of efficient, multicolor LEDs that meet or beat the low cost of their incandescent and CFL counterparts.