Presenter: Dr. Liyuan Han
National Institute for Materials Science, Japan
Topic: Efficient and Stable large-area Perovskite Solar Cells
Time: 09:30AM, April 28(Thursday)
Location: Conference Room B, BLDG 909-1F
The recent dramatic rise in power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) has triggered intense research worldwide. However, high PCE values have often been reached with poor stability at an illuminated area of typically less than 0.1 square centimeter. Here, we put our focus on two aspects: one is improving the reproducibility of device performance through controlling the morphology and uniformity of photoactive and charge transport layers in the solar cells; the other is increasinguniformity of the carrier extraction layer. For example, we developed a new method for fabricating uniform CH3NH3PbI3 layer with using uncrystallised PbI2 precursor films, which overcame the problem of incomplete conversion and uncontrolled particle sizes of perovskite, thus greatly increasing the film uniformity and reproducibility. For the purpose of developing new charge transport materials with low hygroscopicity and high carrier mobility, we used heavily doped inorganic charge extraction layers in planar PSCs to achieve very rapid carrier extraction, even with 10- to 20-nanometer-thick layers, avoidingpinholes and eliminating local structural defects over large areas. The robust inorganic nature of the layers allowed for the fabrication of PSCs with an aperture area >1 square centimeter that have a PCE >18%, as certified by an accredited photovoltaic calibration laboratory. Hysteresis in the current-voltage characteristics was eliminated; the PSCs were stable, with >90% of the initial PCE remaining after 1000 hours of light soaking.
Dr. Liyuan Han is the director of photovoltaic materials unit, National Institute for Materials Science (NIMS). He received a doctor’s degree from the University of Osaka Prefecture in 1988. He worked at SHARP Corporation since 1993 and moved to current position since 2008. Through his career, he has renewed the world record efficiency of dye-sensitized solar cells (cell and module) for several times. Recently, he moved to research perovskite solar cells. He is an inventor in more than 100 patents and an author in ca 200 scientific publications in the field of next generation solar cells. His current research interests involve fundamental research in perovskite solar cells, dye-sensitized solar cells, and organic solar cells.
Contact: Prof. Youyong Li