Japanese group claims record perovskite efficiency
A research group at the Japanese National Institute for Materials Science (NIMS) Photovoltaic Materials Unit, led by Liyuan Han, has reported 15 percent energy conversion efficiency in perovskite solar cells more than 1cm2. This breakthrough result has been certified at the international public test centre (Calibration, Standards and Measurement Team at the Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology).
The most conversion efficiencies in perovskite solar cells reported so far have been measured using small-sized cells (about 0.1 cm2). A conversion efficiency of 20.1 percent has been reported previously, but the researchers say that the measurement error was large in that study due to the small-sized cells used (0.0955 cm2). Also he report did not present the measurement method.
The NIMS group achieved the 15 percent conversion efficiency by developing a new charge transport material which shows hydrophobicity and high carrier mobility, and successfully improved the stability of perovskite solar cells with this new material. Based on these results, it expanded the solar cell to more than 1 cm square and improved the method to create the device.
On the basis of these outcomes, the group aim to further improve conversion efficiency by developing new carrier transport materials with even higher performance and controlling interfaces in perovskite solar cells.
This research was in part conducted in conjunction with a JST (Japan Science and Technology Agency) sponsored research project, 'Device physics of dye-sensitized solar cells' under the research area 'Creative research for clean energy generation using solar energy' in the Core Research of Evolutional Science & Technology (CREST) program.
This study was presented at the International Conference on Hybrid and Organic Photovoltaics 2015 held in Rome, Italy, from May 10 through 13.