title: Optimization of the dye-sensitized solar cell performance by mechanical compression.
abstract: In this study, the P25 titanium dioxide (TiO2) nanoparticle (NP) thin film was coated on the fluorine-doped tin oxide (FTO) glass substrate by a doctor blade method. The film then compressed mechanically to be the photoanode of dye-sensitized solar cells (DSSCs). Various compression pressures on TiO2 NP film were tested to optimize the performance of DSSCs. The mechanical compression reduces TiO2 inter-particle distance improving the electron transport efficiency. The UV-vis spectrophotometer and electrochemical impedance spectroscopy (EIS) were employed to quantify the light-harvesting efficiency and the charge transport impedance at various interfaces in DSSC, respectively. The incident photon-to-current conversion efficiency was also monitored. The results show that when the DSSC fabricated by the TiO2 NP thin film compressed at pressure of 279 kg/cm(2), the minimum resistance of 9.38 Ω at dye/TiO2 NP/electrolyte interfaces, the maximum short-circuit photocurrent density of 15.11 mA/cm(2), and the photoelectric conversion efficiency of 5.94% were observed. Compared to the DSSC fabricated by the non-compression of TiO2 NP thin film, the overall conversion efficiency is improved over 19.5%. The study proves that under suitable compression pressure the performance of DSSC can be optimized.
authors.affiliation: Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan.
authors.forename: Teen Hang
authors.initials: TH
authors.lastname: Meen
authors.affiliation: Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan.
authors.forename: Jenn Kai
authors.initials: JK
authors.lastname: Tsai
authors.affiliation: Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan.
authors.forename: Yu Shin
authors.initials: YS
authors.lastname: Tu
authors.affiliation: Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan.
authors.forename: Tian Chiuan
authors.initials: TC
authors.lastname: Wu
authors.affiliation: Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Wen Dung
authors.initials: WD
authors.lastname: Hsu
authors.affiliation: Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Technology, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Shoou-Jinn
authors.initials: SJ
authors.lastname: Chang
keywords: Conversion efficiency; Doctor blade method; Dye-sensitized solar cells (DSSCs); Mechanical compression; TiO2