Evidence of resonance energy transfer in molecular bilayers on Al2O3 (0001)

Effect of simple aliphatic alcohol thin films on the laser induced excimer fluorescence decay of naphthalene on \alpha-alumina during temperature programmed desorption

“…Details of the experimental set-up have been previously published [4][5][6][7]12], and only a brief outline is given here. For the wavelength resolved TPD, the adlayer of fluorophore was excited by a high pressure Hg lamp, and detected with a diode array spectrometer.…”

“…Some years ago, excimers of aromatic molecules were observed in solutions [3] and more recently they have also been detected in vapor deposited molecular adlayers [4][5][6][7]12]. Recently, the effect of several aliphatic hydrocarbons on the spectral intensity of naphthalene excimers during temperature programmed desorption (TPD) was communicated [6,12].…”

Resonance Energy Transfer from Alkylbenzene Substrates to Naphthalene and Biphenyl Overlayers on Al2O3

“…At deposition temperatures, guest molecules such as naphthalene are known to exhibit fluorescence that is spectrally broad and red-shifted relative to the monomer. − Previous studies of solutions with high concentrations of aromatic molecules have identified the origin of this fluorescence to the formation of transient excimers. − During the TPD, the two different molecules can be made to mix by ensuring that the adlayer of the molecule with the higher desorption temperature is deposited on top. Hence, the molecule deposited adjacent to the surface will percolate through the adlayer above and by choosing molecules with appropriate energy states, energy transfer was observed between the molecules. − In this study, heteroepitaxy is demonstrated as the alkylbenzene substrate ordered and caused the overlayer of naphthalene or biphenyl to crystalize that resulted in enhanced fluorescence from defect sites. Near the desorption temperature, resonance energy transfer (RET) occurred as the substrate passed through the upper layer of naphthalene fluorophores.…”

“…A seed crystal in the ampoule containing the melt was lowered through a sharp temperature gradient, and the result was a boule or a single-crystal ingot. , In this paper, comparable mixed crystals were made by vapor deposition of a bilayer containing the host/guest molecules onto a cryogenically cooled chemically inert surface of Al 2 O 3 and, subsequently, subjecting the bilayer to temperature-programmed desorption (TPD). At deposition temperatures, guest molecules such as naphthalene are known to exhibit fluorescence that is spectrally broad and red-shifted relative to the monomer. − Previous studies of solutions with high concentrations of aromatic molecules have identified the origin of this fluorescence to the formation of transient excimers. − During the TPD, the two different molecules can be made to mix by ensuring that the adlayer of the molecule with the higher desorption temperature is deposited on top. Hence, the molecule deposited adjacent to the surface will percolate through the adlayer above and by choosing molecules with appropriate energy states, energy transfer was observed between the molecules. − In this study, heteroepitaxy is demonstrated as the alkylbenzene substrate ordered and caused the overlayer of naphthalene or biphenyl to crystalize that resulted in enhanced fluorescence from defect sites.…”