Fujitsu has developed a single device that can be used to harvest energy from either light or heat. Previously, dual harvesting of energy could only be done by combining two different devices. Because Fujitsu has been able to create a single device that creates electricity from two different sources it will also be more economical to manufacture. The company sees the main use of this device as a way to power medical devices and sensors.
The company created an organic material that works as a generator for both photovoltaic and thermalelectric harvesting. Because of the materials “high generating efficiency” energy can be harvested from indoor lighting as well as direct sunlight. The same organic material can produce electricity from heat as well. One organic material that generates electricity from two separate types of energy saves money, and keeps production costs down.
Along with the organic material that works as a generator from both light and heat, Fujitsu also used two different semiconductor materials so that the electrical circuits could could change from one mode to the other. Using an N-Type semiconductor, harvests energy from light. Changing to the P-Type semiconductor, harvest energy from heat.
Since Fujitsu’s new device doubles the amount of energy that can be captured, it doesn’t have the disadvantages of solar or thermoelectric only devices. In other words, when there isn’t a light source it will still work with ambient heat and when ambient heat (temperature differentials) isn’t enough to power the device, a light source will.
If either the ambient light or heat is not sufficient to power the sensor, this technology can supply power with both sources, by augmenting one source with the other.
This constant electricity generation can be used in the medical field for “sensors that monitor conditions such as body temperature, blood pressure, and heartbeats – without batteries and electrical wiring.” One environmental use would be in remote sensors that monitor the weather. Without the need for electricity or batteries, the sensors could be placed in hard to reach areas without the need for frequent maintenance.
The prototype device seen in the top photograph, shows that Fujitsu is currently using a flexible substrate. The flexibility of the substrate makes it more comfortable for medical monitoring because it can conform to the patient’s arm, leg or chest unlike other bulky uncomfortable devices.
The projected target year for the commercial introduction of the new device is 2015. In between now and then Fujitsu will certainly come up with new uses for the device as well as refinements of the current prototype.
All photographs and diagrams are courtesy of Fujitsu.