title: Random nanowires of nickel doped TiO2 with high surface area and electron mobility for high efficiency dye-sensitized solar cells.
abstract: Mesoporous TiO(2) with a large specific surface area (~150 m(2) g(-1)) is the most successful material in dye-sensitized solar cells so far; however, its inferior charge mobility is a major efficiency limiter. This paper demonstrates that random nanowires of Ni-doped TiO(2) (Ni:TiO(2)) have a dramatic influence on the particulate and charge transport properties. Nanowires (dia ~60 nm) of Ni:TiO(2) with a specific surface area of ~80 m(2) g(-1) were developed by an electrospinning technique. The band gap of the Ni:TiO(2) shifted to the visible region upon doping of 5 at% Ni atoms. The Mott-Schottky analysis shows that the flat band potential of Ni:TiO(2) shifts to a more negative value than the undoped samples. The electrochemical impedance spectroscopic measurements showed that the Ni:TiO(2) offer lower charge transport resistance, higher charge recombination resistance, and enhanced electron lifetime compared to the undoped samples. The dye-sensitized solar cells fabricated using the Ni:TiO(2) nanowires showed an enhanced photoconversion efficiency and short-circuit current density compared to the undoped analogue. The transient photocurrent measurements showed that the Ni:TiO(2) has improved charge mobility compared with TiO(2) and is several orders of magnitude higher compared to the P25 particles.
authors.affiliation: National University of Singapore, Singapore.
authors.forename: P S
authors.initials: PS
authors.lastname: Archana
authors.forename: E
authors.initials: E
authors.lastname: Naveen Kumar
authors.forename: C
authors.initials: C
authors.lastname: Vijila
authors.forename: S
authors.initials: S
authors.lastname: Ramakrishna
authors.forename: M M
authors.initials: MM
authors.lastname: Yusoff
authors.forename: R
authors.initials: R
authors.lastname: Jose