title: Increased photovoltaic performance by the optimized TiClI4 and AlCl3 surface treatment in dye-sensitized solar cells.
abstract: The surface of TiO2 photoelectrodes coated on F-doped SnO2 (FTO) was modified by soaking it in a TiCl4:AlCl3 mixed aqueous solution with various molar ratios, and then calcining to produce the TiCl4:AlCl3-treated TiO2 photoelectrode (Ti:Al-TiO2/FTO). The highest power conversion efficiency (PCE) was obtained from dye-sensitized solar cells (DSSC) with Ti:Al(5:5)-TiO2/FTO, which was prepared from the mixed solution with the molar ratio of 5:5 (TiCi4:AlCl3). PCE of DSSC with Ti:Al (5:5)-TiO2/FTO was improved by ca. 19.6%, compared to that of the reference device with Ti:Al (10:0)-TiO2/FTO (i.e., TiO2-coated TiO2/FTO) due to an enhancement in both short-circuit photocurrent (J(sc)) and open-circuit voltage (V(oc)). A series of measurements such as UV-visible absorption, electrochemical impedance, open circuit voltage decay and dark current revealed that the increase in J(sc) was attributed to the improvement of electron collection efficiency by a prolonged electron lifetime, and the suppression of the charge recombination between injected electrons and I3(-) ions was found to increase the V(oc) value of the device with Ti:Al(5:5)-TiO2/FTO.
authors.forename: Ju Hee
authors.initials: JH
authors.lastname: Oh
authors.forename: Dae-Hwan
authors.initials: DH
authors.lastname: Kim
authors.forename: Sang-Ju
authors.initials: SJ
authors.lastname: Lee
authors.forename: Giseop
authors.initials: G
authors.lastname: Kwak
authors.forename: Yoon Soo
authors.initials: YS
authors.lastname: Han