title: Density functional investigation and some optical experiments on dye-sensitized quantum dots.
abstract: Dye-sensitized quantum dots (QDs) are promising candidates for dye-sensitized solar cells (DSSCs). Here, we report steady state (absorption and photoluminescence) optical measurements on several sizes of CdS QDs ligated with Coumarin 343 dye (C-343) and two different solvents, viz., chloroform and toluene. We further report detailed first principles density functional theory and time-dependent density functional theory studies of the geometric, electronic and optical (absorption and emission) properties of three different sized capped QDs, ligated with C-343 dye. The absorption spectrum shows a QD-size-independent peak, and another peak which shifts to blue with decrease in QD size. The first peak is found to arise from the dye molecule and the second one from the QD. Charge transfer using natural transition orbitals (NTOs) is found to occur from dye-to-QDs and is solvent-dependent. In the emission spectra, the luminescence intensity of the dye is quenched by the addition of the QD indicating a strong interaction between the QD and the dye.
authors.affiliation: Department of Physics, D. J. College, Baraut, Uttar Pradesh 250611, India.
authors.forename: Kalpna
authors.initials: K
authors.lastname: Jain
authors.affiliation: Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
authors.forename: Sreejith
authors.initials: S
authors.lastname: Kaniyankandy
authors.affiliation: Department of Chemistry, J. V. College, Baraut, Uttar Pradesh 250611, India.
authors.forename: Shyam
authors.initials: S
authors.lastname: Kishor
authors.affiliation: Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden.
authors.forename: Ida
authors.initials: I
authors.lastname: Josefsson
authors.affiliation: Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
authors.forename: Hirendra N
authors.initials: HN
authors.lastname: Ghosh
authors.affiliation: Department of Physics, D. J. College, Baraut, Uttar Pradesh 250611, India.
authors.forename: Khundrakpam S
authors.initials: KS
authors.lastname: Singh
authors.affiliation: Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Sumit
authors.initials: S
authors.lastname: Mookerjee
authors.affiliation: Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden.
authors.forename: Michael
authors.initials: M
authors.lastname: Odelius
authors.affiliation: High Pressure and Synchrotron Radiation Physics Divison, Physics Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India. lavanya@barc.gov.in lmrjgd@gmail.com.
authors.forename: Lavanya M
authors.initials: LM
authors.lastname: Ramaniah