Energy Transfer in Molecular Layer-by-Layer Films of Water-Soluble Perylene Diimides

Abstract

Multilayer films of water-soluble anionic and cationic perylene diimide (PDI) moieties have been prepared using the molecular layer-by-layer method described in an earlier publication (Tang, T. J.; Qu, J. Q.; Müllen, K.; Webber, S. E. Langmuir 2006, 22, 26-28) and the fluorescence intensity compared with and without a base layer prepared using an anionic terrylene diimide dye (n-TDI), which serves as an energy-trapping layer for the PDI exciton. The fluorescence quenching data could be fit equally well to a modification of a model used by Kuhn to describe energy transfer from a J aggregate or a model developed by Kenkre and Wong to describe excitonic transfer. For both models, we obtain a characteristic energy-transfer distance on the order of 5.4 nm. Fluorescence quenching of the PDI via a single Förster energy-transfer step to the n-TDI layer is ruled out on the basis of the observed power-law dependence. We also consider a model in which the excitation is trapped at the outermost surface. This model provides a reasonable fit to the data only if the Kuhn relationship is used.

Does Conjugation Help Exciton Dissociation? A Study on Poly(p‐phenylene)s in Planar Heterojunctions with C60 or TNF

“…Light intensities were recorded with a Hamamatsu S1337-33BQ photodiode. The internal electric field was calculated as F = (V − V oc )/d, with applied external voltage V, open-circuit voltage V oc (typically between 0.5 and 0.7 V, see the Supporting Information) and active film thickness d. The photocurrent quantum yield J(F) was calculated taking into account photocurrent density of the solar cell, illumination light intensity, and the exciton diffusion length (typically around 10 nm) [35][36][37][38] derived by comparison between absorption and photocurrent spectra.…”

Terpyridine‐Functionalized Surfaces: Redox‐Active, Switchable, and Electroactive Nanoarchitecturesgland

“…[ 29 , 30 ] Furthermore, well-defi ned SAMs have been achieved on various surfaces; multilayer assemblies were obtained on quartz substrates by a layer-by-layer approach. [ 31 ] The stepwise growth of nanowire-type multilayers was investigated by SIMS and UV-vis absorption spectroscopy (using a semitransparent gold foil as the substrate; see Figure 2 b). Atomic force microscopy (AFM) measurements of patterned surfaces, e.g., a gold surface covered with octadecanethiol (ODT) lines by micro contact printing (the ODT-free areas were subsequently covered with a SAM of 1 and 2 ), confi rmed the stepwise growth of the fi lm.…”

Efficient Visible‐Light Emission from Dye‐Doped Mesostructured Organosilica

“…[15,32] For the mixed film consisting of mOPV-F and Rub, the R 0 is approximately 3.7 nm. On the other hand, X-ray diffraction and TEM observations of the mOPV-F film indicate that the periodicity of the wormhole-like mesochannel array is 10-14 nm.…”

“…[31] The critical Förster radius (R 0 ), which is a theoretical indicator of energy-transfer probability assuming direct resonance energy transfer without exciton migration for each donor-acceptor pair, was estimated from the spectral overlap shown in Figure 2b according to a conventional calculation method (see Supporting Information). [15,32] For the mixed film consisting of mOPV-F and Rub, the R 0 is approximately 3.7 nm. On the other hand, X-ray diffraction and TEM observations of the mOPV-F film indicate that the periodicity of the wormhole-like mesochannel array is 10-14 nm.…”