NREL - Page 7

Researchers from Brown University, the National Renewable Energy Laboratory (NREL) and the Chinese Academy of Sciences' Qingdao Institute of Bioenergy and Bioprocess Technology came up with a way of "flipping a chemical switch" that converts one type of perovskite into another - a type that has better thermal stability and is a better light absorber. This achievement could be one more step toward bringing perovskite solar cells to the mass market.

The researchers demonstrated their new technique for making solar cells that can be more stable at moderate temperatures than the perovskite solar cells that are currently being developed; The technique is said to be simple and has the potential to be scaled up.

Researchers at the National Renewable Energy Laboratory (NREL) announced that they have figured out a pathway for dealing with the heat loss problem by deploying hot-carrier technology in perovskite solar cells. Hot carrier solar cells offer simplicity of design, low cost, and high efficiency, but are a long way from being commercialized, as one big challenge is revving up the kinetic energy transfer in order to prevent energy loss.

This recent study provides a pathway for pushing perovskite levels upwards, possibly as high as 66%. It determines that charge carriers created by absorbing sunlight by the perovskite cells encounter a bottleneck where phonons (heat carrying particles) that are emitted while the charge carriers cool cannot decay quickly enough. Instead, the phonons re-heat the charge carriers, thereby drastically slowing the cooling process and allowing the carriers to retain much more of their initial energy for much longer periods of time. This potentially allows this extra energy to be tapped off in a hot-carrier solar cell.

Researchers from Brown University and the National Renewable Energy Lab (NREL) managed to attain better than a 15% energy conversion efficiency from perovskite solar cells larger than one square centimeter area, by using a newly developed fabrication method.

Efficiency of over 20%, which rivals traditional silicon cells, has already been reported in perovskite cells, but such high efficiency ratings have been achieved using cells only a tenth of a square centimeter in size, too small to be used in a solar panel. This research, however, shows that it is feasible to obtain 15% efficiency on cells larger than a square centimeter through improved processing.