Special Quantum Dots could Improve Transparent Solar Cells
An immense amount of energy pours onto the surface of the Earth from the Sun every day, so naturally we are trying to find ways to harness it. In the future it may be that our windows will be converting some of that energy into electricity. Researchers at Los Alamos National Laboratory have recently developed a special quantum dot that addresses one issue preventing those windows from becoming a reality.
Quantum dots are nanoscale semiconductor crystals that can be tuned to have specific optical properties. By adding them to glass a luminescent solar concentrator (LSC) can be created, as the dots will absorb some of the light that passes through the window and then re-emit it as a different color. This light will then travel through the glass until it reaches a solar panel at the edge, which converts it into electricity. One of the issues with such an LSC is that the quantum dots will absorb some of the light they emit, which causes some energy to be lost. The LANL researchers addressed this by creating quantum dots with separated components for absorption and emission. This allows it to emit a color of light that the dots will not absorb.
When tested the LSC the researchers built demonstrated almost no energy loss due to re-absorption. It also achieved a good harvesting efficiency of 10% of photons that could be absorbed, without compromising the sample's transparency.
Source: Los Alamos National Laboratory