A significant disadvantage of solar panels is the need for sunlight to generate electricity. It has been observed that for a space-oriented device in the earth, it has cold temperature, and the energy flowing out of the device can be collected by the same optoelectronic physics we use to use solar energy. AIP's "Applied Physics Letter" recently published a new study that attempts to provide a possible way for power generation such as solar cells to power electronic devices at night.
An international team of scientists has demonstrated for the first time that it is possible to produce measurable electricity directly in the diode from the cold of the universe. Infrared semiconductor devices face the sky and use the temperature difference between the Earth and space to generate electricity. "The vastness of the universe is a thermodynamic resource," said Fan Shanhui, author of the paper. In optoelectronic physics, there is indeed a very beautiful symmetry between the received radiation and the emitted radiation. ”
Unlike conventional solar cells, which utilize input energy, the negative illumination effect allows electrical energy to be collected as heat exits the surface. However, today's existing technologies do not effectively capture the energy at these negative temperature differences. By directing their devices to a temperature close to absolute zero, the team was able to find a large enough temperature difference to generate energy through early design. This is a schematic of an experimental infrared photodiode that generates electricity directly from cold space.
Musashino, another author of the paper, said: "At present, through this experiment, we can generate energy far below the theoretical limit."
The team found that their negative lighting diodes generate about 64 milliwatts of electricity per square meter, although the power is small, this is an important proof that researchers can improve this by increasing the quantum optoelectronic properties of the materials they use. a little. The calculations after the diodes generate electrical energy show that when considering the atmospheric effect, the current device theoretically produces nearly 4 watts of electrical energy per square meter, about one million times that of the group's devices, enough to provide night-time power machinery.
In contrast, today's solar panels generate between 100 and 200 watts per square meter.
Although the results of the study show the prospect of ground-based equipment facing the sky, Fan Shanhui said that the same principle can also be used to recover the waste heat of the machine. Currently, he and his team are working to improve the performance of the device.