Highly Efficient Dye-Sensitized Solar Cells
Liyuan Han
Photovoltaic Materials Unit, National Institute for Materials Science
1-2-1 Sengen Tsukuba, Ibaraki, 305-0047, Japan
Dye-sensitized solar cells (DSCs) have been widely investigated as a next-generation solar cell because of low manufacturing cost. In this presentation, strategy for improving efficiency of DSCs was reported. The method for improvement of shirt circuit density (Jsc), open circuit voltage (Voc) and fill factor (FF) were investigated based on the equivalent cirsuit. It is found that the series-internal resistance decreases with increase of the roughness factor of the counter electrodes, the decrease of the thickness of the electrolyte layer and the sheet resistance of the transparent conducting oxide. For the purpose of improving Jsc, dependence of incident photon to current conversion efficiency (IPCE) spectra on haze of TiO2 film was investigated. IPCE is widely increased with increase of the haze of TiO2 film, especially in infrared region. Furthermore, a small donor-acceptor type co-adsorbent for black dye sensitized DSCs was designed and synthesized, which can effectively increase JSC by offsetting the competitive light absorption of I-/I3- and improve VOC by introducing butyloxyl chains into the molecule to avoid dye aggregation and reduce the charge recombination. New efficiency record of 11.4% was achieved by using the novel co-adsorbent, which was certified by Research Center for Photovoltaic, National Institute of Advanced Industrial Science and Technology (AIST, Japan).
Finally, the current state and futher respect of comicatisation of DSCs will be detailed.
Dr. Han is a director of photovoltaic materials unit, National Institute for Materials Science. He received a doctor’s degree from the University of Osaka Prefecture in 1988. During 1990 - 1993, he worked in Dainippon Ink & Chemicals Inc. on organic photoconductor materials. He then moved to SHARP Corporation. He has been investigating dye-sensitized solar cells, especially, improving the conversion efficiency of cells and sub-modules, and developing new sensitized dyes, since 1996. He moved to current position from June 2008. His major researches include proposing the equivalent circuit model of DSCs and applying the back-contact model into dye-sensitized solar cells. Through his career, he has made great accomplishments in the field including achieving the world record efficiency of 11.4% in dye-sensitized solar cells. He is inventor in about 100 patents and author in ca 80 scientific publications in the field of dye sensitized solar cells. His current research interests involve foundational research dye-sensitized solar cells, organic solar cells and quantum dot solar cells.
