Energy transfer in porous-silicon/laser-dye composite evidenced by polarization memory of photoluminescence

Abstract

The optical properties of nanocomposites are studied for rhodamine B (RhB) dye molecules embedded in nanoscale porous silicon (PS) and porous silica (P-silica). The samples are prepared by simple immersion of porous matrix substrates in RhB solutions. Fourier transform infrared spectroscopy suggests that RhB molecules fully penetrate into the porous matrix. Efficient photoluminescence has been observed in all experimental nanocomposites. The measurement of the polarization memory (PM) effect provides a clear evidence for the presence of an excitation energy transfer from PS to RhB molecules, in contrast to the PM behavior in RhB∕P-silica composite.

Photoluminescence‐Based Sensing With Porous Silicon Films, Microparticles, and Nanoparticles

“…To complicate matters further, there is good evidence that a significant amount of energy exchange occurs between the quantum-confined structures in the porous Si matrix. [96][97][98][99] Various approaches to obtain meaningful lifetime data from porous Si have been attempted, including the use of a stretched exponential fit [93,100] and calculation of an ''effective t'' based on integration of the intensity versus time curve. [23,91] The data are usually self-consistent, and at least they allow relative rate comparisons to be made.…”

“…[101] Our experiments, and those of McLendon, Fauchet, Meyer, and others have provided a fairly complete picture of the excited state energetics of porous Si. [92,93,99,101,102] An interesting medical application involving the energy transfer quenching mechanism has been proposed by Fujii, Kovalev, and co-workers. We first observed and quantified the efficient quenching of porous Si photoluminescence by oxygen in 1997.…”

Silicon Nanocrystals in Porous Silicon and Applications

“…Recently, it was demonstrated by using polarization memory of PL [226]. Generation of singlet oxygen at room temperature mediated by energy transfer from photoexcited PSi is dealt with in Chapter 19.…”

Effect of high-pressure water-vapor annealing on energy transfer in dye-impregnated porous silicon

“…Analysis of the PL and its polarization memory (PM) has shown [12] that energy transfer can take place from Si nanocrystals to dye molecules in RhB-impregnated PS samples. PS is therefore a good host for potential functional devices.…”