Laser-blasted ‘black metal’ could make solar technology 15 times more efficient
Scientists who are looking for means of amplier the capacities of solar energy generators have discovered a method that can increase their effectiveness of a factor of 15.
The breakthrough lies in a unique “black metal” and laser developed by researchers In the past five yearsthat they now hope to use in thermoelectric solar generators (STEGS).
Stegs are a type of electronic device with a solid state which converts thermal energy into electricity via the Seebeck effect – a phenomenon that occurs when the temperature difference between the materials moves the charged particles and creates an electromagnetic force (EMF) or a tension.
A STEG contains semiconductor materials sandwiched between a “hot” side and a “cold” side. When the hot side is heated – either by the sun or another source of thermal energy – the movement of the electrons through the semiconductor material creates a electric current.
The challenge with existing STEGS is that they are extremely ineffective, converting less than 1% of sunlight into electricity. This contrasts with photovoltaic solar panels that you will generally find attached to people’s houses, which convert around 20% of the light they receive in electricity.
In relation: The breakthrough of nanoparticles could bring the “holy grail” of solar energy within reach
However, in a new study published on August 12 in the journal Light: Science and applicationsThe researchers used laser treated metals, also known as “black metal” because of their deep and black ink appearance, to stimulate the energy efficiency of a thermoelectric solar generator by a factor of 15.
Laser treatment
The method involved exploding a piece of tungsten with extremely fast and precise laser pulses to climb microscopic grooves in its surface. These “engravings on a nanometric scale allowed the tungsten to absorb more thermal radiation and maintain it longer.
Laser pulses also have the effect of turning the surface of any metal black, increasing their ability to absorb heat. The researchers then covered the black tungsten with a piece of plastic to create a “mini greenhouse” which trapped even more heat.
For the cold side of the STEG, the scientists took an ordinary piece of aluminum and again castigated it with laser pulses. The tiny engravings in the metal created a “super high micro-structured” heat dissipator “that the team affirmed was twice as effective to dissipate heat from a typical aluminum thermal dissipator.
To test the system, the researchers used it to feed an LED under the light of the simulated sun. A typical STEG could not light up the LED even when it is exposed to light 10 times stronger than normal sunlight. However, with both sides treated using metal black, the device turned on the LED with full light under the light five times stronger than normal sunlight – equivalent to an increase of 15 times of the power.
Although it probably does not replace the solar farms so early, technology could possibly be used for the internet sensors of low -power wireless objects (IoT) or portable devices, or serve as off -network renewable energy systems in rural areas, researchers said in a statement.
“For decades, the research community has focused on improving semiconductor materials used in Stegs and has produced modest gains in global efficiency”, ” Chunlei GuoThe study co-author, professor of optics and physics, and main scientist at the laser energy laboratory of Rochester University, in the press release.
“In this study, we do not even touch semiconductor materials – we rather focused on the hot and cold sides of the device.
