ABOUT THE SPEAKER:
Professor Eric Wei-Guang Dia, Distinguished Professor at Department of Applied Chemistry and Science of Molecular Science, National Chiao Tung University.
He received his Ph.D. in Physical Chemistry from National Tsing Hua University, Taiwan, in 1991. Before joining at Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan, as a faculty member since 2001, he worked as a postdoctoral fellow at Emory University (1993-1995), University of Queensland (1995-1996), Stanford Research Institute, International (1996-1997) and California Institute of Technology (1997-2001).
He is interested on studying relaxation kinetics in condensed matters, in particular interfacial electron transfer and energy transfer dynamics in many solar energy conversion systems. His current research is focusing on the developments of novel functional materials for next-generation solar cells, including perovskite solar cells (PSC). He received “Outstanding Research Award” from MRS Spring Meeting & Exhibit on April, 2014 and “Sun Yat Sen Academic Award” from Sun Yat Sen Academic and Cultural Foundation on October, 2014. He has published over 150 peer-reviewed papers with H-index 47.
ABSTRACT:
The development of all solid-state thin-film solar cells has reached a new milestone when the devices made of organometallic lead halide perovskite materials were reported with power conversion efficiency (PCE) exceeding 20 %. The key issue to make a device with a great photovoltaic performance for perovskite solar cells is to control the film morphology of perovskite under different experimental conditions.
In this lecture, I will demonstrate how the film morphology of perovskite can be controlled via varied synthetic approaches. Typical n-type device has a structural configuration FTO/TiOx/TiO2/CH3NH3PbI3/Spiro-OMeTAD/Au whereas that of a p-type device is configured as ITO/PEDOT:PSS/CH3NH3PbI3/PCBM/Al. For n-type devices, varied mesoporous TiO2 nanostructures were applied to show the morphological effect of the scaffold on the device performance with a mesoscopic heterojuction; for p-type devices, varied additives were applied to control the formation morphology of the perovskite nanocrystals with a planar heterojunction.
Photo-induced absorption (PIA) spectra and nanosecond transient absorption (ns-TAS) kinetics were also performed to understand the electron-hole recombination rates responsible for the corresponding device performances. Measurements of power dependence on emission intensities vs excitation power densities were also performed and an Auger-type energy transfer model was utilized to rationalize the observed relaxation dynamics.