Perovskite solar cells use Mesoporous titanium dioxide as the electron transport layer. This electron-transport layer shows low electron mobility and is also susceptible to adverse photocatalytic events under ultraviolet light.
Scientists at EPFL have found an innovative way to increase the performance and maintain it at a high level in perovskite solar cells, even at large scales. They replaced the efficiency and scalability of perovskite solar cells by replacing their electron-transport layers with a thin layer of quantum dots.
Quantum dots act as semiconductors and emit light of specific wavelengths (colors) when they are illuminated.
By replacing the titanium dioxide electron-transport layer of their perovskite cells with a thin layer of polyacrylic acid–stabilized tin(IV) oxide quantum dots, they were able to enhance the device’s light-capturing capacity. This also suppressed nonradiative recombination, an efficiency-sapping phenomenon that sometimes takes on the interface between the electron-transport layer and the actual perovskite layer.
The quantum dot layer boosted the power-conversion efficiency of solar cells by 25.7% (certified 25.4%). It also offered high operational stability.
This study was done in collaboration with Ulsan National Institute of Science and Technology, University of Ulsan, Zurich University of Applied Sciences, Uppsala University.
Journal Reference:
- Minjin Kim, Jaeki Jeong et al. Polymer-stabilized SnO2 quantum dot electron transporters for efficient perovskite solar cells Science 21 January 2022. DOI: 10.1126/science.abh1885