Energy transfer from phosphorescent blue-emitting oxidized porous silicon to rhodamine 110

Abstract

Nanocomposites consisting of oxidized porous Si (OPSi) impregnated with rhodamine 110 (Rh110) molecules are characterized in terms of luminescence properties. The photoluminescence and its polarization memory strongly indicates a trace of energy transfer from the fast blue luminescence band of OPSi to the green one of Rh110. Time-resolved experiments showed that energy transfer to Rh110 also takes place from the long-lived blue phosphorescence of OPSi. The transfer channel from nonradiative states of OPSi to Rh110 was also found. The ability of OPSi to harvest and transfer absorbed photon energy to a guest is promising for applications in optoelectronics and biology.

The photophysics of porous silicon: technological and biomedical implications

“…Rhodamine 110 has a relatively narrow absorption band with a peak at about 500 nm, while unoxidized pSi emits in the red-orange region and is not expected to efficiently transfer energy to rhodamine 110, which has indeed been observed. 97 On the other hand, as noted above, OpSi luminesces in the blue-green region and, hence, can be an efficient energy donor for rhodamine 110. Analysis of PL spectra at a delay after the exciting laser pulse showed that energy transfer in the OpSi-Rh110 system occurred within a relatively long interval (B100 ms).…”

“…One can select the optimal resonance conditions for a given donor and a given acceptor by varying the pore size. Many studies have dealt with pSi-based nanocomposites capable of energy transfer from pSi to the adsorbed molecules [97][98][99][100] or vice versa. [101][102][103] In terms of photonics and laser physics, of interest are studies on excitation transfer from pSi to some rhodamine dyes, 97,100,104,105 whose absorption spectra overlap with the PL spectrum of pSi.…”

“…Many studies have dealt with pSi-based nanocomposites capable of energy transfer from pSi to the adsorbed molecules [97][98][99][100] or vice versa. [101][102][103] In terms of photonics and laser physics, of interest are studies on excitation transfer from pSi to some rhodamine dyes, 97,100,104,105 whose absorption spectra overlap with the PL spectrum of pSi. Note that the pSi absorption spectrum is substantially wider than those of the dyes are, which makes it possible to excite the dyes by light of various wavelengths.…”

“…It has also been found that, although OpSi can adsorb more dye molecules than unoxidized pSi, excitation is transferred to the dye from OpSi less efficiently than from pSi because of an increased distance between the dye molecules and nc-Si. 100 Interesting results were obtained in the study 97 on energy transfer in the systems of pSi and OpSi impregnated with rhodamine 110 (pSi-Rh110 and OpSi-Rh110, respectively). Rhodamine 110 has a relatively narrow absorption band with a peak at about 500 nm, while unoxidized pSi emits in the red-orange region and is not expected to efficiently transfer energy to rhodamine 110, which has indeed been observed.…”

(Invited) Blue Phosphorescence in Oxidized Nano-Porous Silicon

“…This blue emission includes an intrinsic phosphorescence (Ph) band which exhibits a lifetime of several seconds because of radiative transitions from triplets to ground states (10). We have also demonstrated that the energy related to the Ph emission can be efficiently transferred from OPSi to rhodamine 110 molecules (11).…”