Most solar panels are in the 20 to 25% efficiency range. This new most efficient solar cell is nearly 40% efficient.
The scientists at the US Department of Energy’s National Renewable Energy Laboratory (NREL) have broken the world record for the efficiency of a solar cell by creating a cell with 39.5% efficiency.
You can read the academic research here in the May issue of the journal Joule.
This cell uses “thick quantum well superlattices” to power triple-junction solar cells with 39.5% efficiency.
This is currently the most efficient solar cell on Earth. The previous record was also set at NREL in 2020 with a cell of 29.2% efficiency.
How do quantum well solar cells work?
Quantum well is one of technologies on the cutting edge of the newest generation of photovoltaic (PV) solar cells. The goal is to achieve maximum efficiency at lower cost.
The quantum well concept uses multi-junction cells with smaller bandgap material that absorb lower energy photons and larger bandgap materials that absorb higher energy photons.
Each layer gets a chance to absorb energy as light passes through the cell. The controlled layer thicknesses control how the electrons move in the cell.
This technology has been tested by NASA in the Silicon Germanium Quantum Well Solar Cell.
The record-breaking solar cell from NREL also has applications in space where it will have a 34.2% efficiency.
What makes this cell so efficient?
The unique design of the cell (the cell architecture) is called “inverted metamorphic multijunction” (or IMM) design. The different junctions are built of different materials as follows:
- Top: gallium indium phosphide
- Center: gallium arsenide
- Bottom: gallium indium arsenide
Since these materials absorb energy from light at different wavelengths, more energy can be captured from natural sunlight.
The special quantum well technology is also applied in the center layer and this ensures the electrons in that layer are controlled for maximum energy production.
As you might have guessed, these types of cells are expensive to produce at the moment but as we know, technology gets cheaper over time and might in the near future become ready for mass production.