March 21 (Renewables Now) - The Los Alamos National Laboratory (LANL) in the US and partners have created 2D layered hybrid perovskites which the scientists say can allow greater efficiency for solar cells and light-emitting diodes (LEDs).
Jean-Christophe Blancon, lead author on a paper released earlier in March, explains that the material represents a layered compound - a stack of 2D layers of perovskites with nanometer thickness, separated by thin organic layers. The 2D, near-single-crystalline “Ruddlesden-Popper” thin films have an out-of-plane orientation so that uninhibited charge transport occurs through the perovskite layers in planar devices. At the edges of the perovskite layers the researchers discovered “layer-edge-states” which according to them are key to making solar cells with efficiencies above 12% and boosting LED high fluorescence efficiency. They say the spontaneous conversion of excitons to free carriers is seen as the key to making better photovoltaic (PV) and light-emitting thin-film layered materials.
Explaining the image above: How it works, from sunshine (yellow beam) to LED light and photovoltaics -- Edge-states at the edges of the 2D perovskite layers lead to dissociation of electron-hole pairs (excitons) to free carriers for efficient photovoltaics of more than 12 percent (left). Dissociated carriers captured and located at the edge-states live longer while being protected from loss mechanisms (right), which results in efficient fluorescence of a few tens of percent applicable to next-generation LEDs. (top) Material structure sketching the stacking of nanometer-thick layers of 2D perovskite and organic spacing layers.
Co-author Mercouri Kanatzidis of Northwestern University says the 2D hybrid perovskites research has so far only scratched the surface and the team expects more from these “truly amazing systems”.