International. A team of researchers has broken the efficiency record for silicon-based solar cells by producing a cell that was tested to be 26.3 percent efficient, a 0.7 percent increase over the previous record.
In their paper published in the journal Nature Energy, the team describes the techniques they used to improve efficiency and their plans to continue reaching the theoretical limit of 29.1 percent.
As is well known, the issue of taking advantage of the sun's energy has been advancing, mainly through the use of solar cells. However, industry-standard silicon-based solar cells still cannot compete with coal due to the relatively high cost involved in making them.
One way engineers hope to overcome this problem is to make individual solar cells produce more energy, i.e. increase their efficiency, which would mean that end users could buy fewer of them to meet their needs. In this new effort, the Kaneka Corporation team has found a way to improve various parts of the production process.
To make their cell, the researchers started with a crystalline silicon disk that was thinner than standard cells — just 165 micrometers. Its surface was then etched to minimize the reflection of light. Both sides were then coated with amorphous silicon to reduce the loss of charge carriers. Efficiency was further improved by implementing the company's proprietary technology, heterojunction and interdigitated electrodes. The team also moved the electrode grid from the front of the cell to the back, allowing an increasing amount of sunlight to enter the cell while minimizing losses in the optics.
The new record was measured by the Fraunhofer Institute for Solar Energy Systems in Freiburg for accuracy, proving the team's claims. However, researchers have not yet determined to what extent their technique can be ported to industrial processing. Therefore, it is not yet clear if or when it could result in more efficient products sold to consumers. The team has also announced its intentions to continue efforts to improve efficiency.
Source: https://techxplore.com/
