Role of Resonance Energy Transfer in Light Harvesting of Zinc Oxide-Based Dye-Sensitized Solar Cells

Abstract

In this contribution we have studied the dynamics of light harvesting of ZnO nanoparticles (NPs) to a surface adsorbed sensitizing dye (SD) N719. By using the picosecond resolved Förster resonance energy transfer (FRET) technique we have explored that the excited ZnO NPs resonantly transfer visible optical radiation to the SD N719. The consequence of the energy transfer on the performance of the overall efficiency of a model ZnO NP-based dye-sensitized solar cell (DSSC) has also been explored. We have demonstrated that the overall efficiency of a ZnO NP-based solar cell significantly depends on the presence of high-energy photons in the solar radiation. In a control experiment on a model TiO 2 NP-based solar cell it has been demonstrated that the presence of high-energy photon has a minimal effect on the performance of the cell as the TiO 2 NPs are incapable of harvesting high-energy photons from solar radiation. The possibility of the back electron transfer from the excited NPs to the SD has also been investigated by studying the NPs in the presence of an ideal electron accepting organic molecule, benzoquinone (BQ). The time constants and nonradiative rate constant obtained for the ZnO/N719 system are found to be different from those of the ZnO/BQ system, which rules out the possibility of back electron transfer from ZnO NPs to SD N719. Moreover, the observed FRET dynamics in the light harvesting process of the nanocrystalites may be efficient in the further use of the nanoparticles in the development of new photodevices.

Ultrafast dynamics at the zinc phthalocyanine/zinc oxide nanohybrid interface for efficient solar light harvesting in the near red region

“…In most cases, polypyridyl ruthenium complexes are likely choices for such applications [1][2][3][4]. While the complexes work reasonably well in visible light, the main drawback of such complexes is a lack of reasonable absorption in the near-IR region.…”

Photochemical performance of ZnO nanostructures in dye sensitized solar cells

“…The area of spectral overlap region is significant for ZnO rods having an emission band close to the absorption band of N719 dye molecule. The overlapped region is minimum for ZnO particles where the emission band maximum is away from the absorption band maxima of N719 dye molecule at 524 nm in particular [36]. In order to establish the phenomena of energy transfer from ZnO to the sensitizer N719 dye we have measured the fluorescence quantum yield (QY) of the fabricated ZnO films and compared the same after N719 dye adsorption for 2h.…”

ZnO Nanostructures for Alternate Energy Generation

“…In order to comprehend the charge transfer mechanisms in a ZnO nanoparticle/N719 complexation, the photoluminescence (PL) from the ZnO nanoparticles was taken to observe if the PL overlaps with the absorption spectrum of the N719 dye [43]. Figure 3.7 shows a HRTEM micrograph of the ZnO nanoparticles and their UV/Vis absorption spectra and that of dye N719.…”

“…The photoluminescence (PL) spectrum of the ZnO NPs upon excitation with a 375 nm laser (Fig. 3.7) shows a significant spectral overlap with [43] that of the absorption of the N719. This indicates the possibility of transfer of energy from ZnO to the N719 molecules on photoexcitation.…”