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.