Physical mechanism of photoinduced intermolecular charge transfer enhanced by fluorescence resonance energy transfer

Abstract

In this paper, photoinduced intermolecular charge transfer (PICT) and fluorescence resonance energy transfer (FRET) in donor-acceptor systems have been investigated experimentally and theoretically. We attempt to investigate the natural relationship between FRET and PICT, and reveal the advantages of FRET enhanced PICT. The driving force for PICT in the FRET system equals the reorganization energy, which gives barrier-less charge transfer according to Marcus theory. The rates of PICT in the FRET system can be estimated with our simplified Marcus equation. Our results can promote the deeper understanding of the nature of FRET enhanced PICT, and benefit rational design for the use of the FRET system in organic solar cells.

Plasmon‐Enhanced Fluorescence Resonance Energy Transfer

“…Note that there are two fluorescence peaks for the donor from Figure (a) (one is a weak peak at about 560 nm, and another is a strong peak at about 625 nm) . From Figure (b), a strong fluorescence peak occurs at about 730 nm, and there is no fluorescence peak from 450 to 600 nm (excitation range) .…”

“…[34] From Figure 5 (b), a strong fluorescence peak occurs at about 730 nm, and there is no fluorescence peak from 450 to 600 nm (excitation range). [34] Note that FRET indeed occur, which can be seen from the diffidence of the variation tendency of the two peaks at 630 nm and 730 nm (the former is decrease and latter is increase) (see Figure 6 (a-d)). [34] Sun et al also calculated the efficiency of FRET using eq.…”

“…Note that J51 and ITIC are two of the best materials for organic solar cells, because they have strong FRET effects in the red region in Figure 4 because of the overlap between J51 and ITIC in the region from 500 to 600 nm. [34] Note that there are two fluorescence peaks for the donor from Figure 5 (a) (one is a weak peak at about 560 nm, and another is a strong peak at about 625 nm). [34] From Figure 5 (b), a strong fluorescence peak occurs at about 730 nm, and there is no fluorescence peak from 450 to 600 nm (excitation range).…”

“…[34] Note that there are two fluorescence peaks for the donor from Figure 5 (a) (one is a weak peak at about 560 nm, and another is a strong peak at about 625 nm). [34] From Figure 5 (b), a strong fluorescence peak occurs at about 730 nm, and there is no fluorescence peak from 450 to 600 nm (excitation range). [34] Note that FRET indeed occur, which can be seen from the diffidence of the variation tendency of the two peaks at 630 nm and 730 nm (the former is decrease and latter is increase) (see Figure 6 (a-d)).…”

“…selected polymer benzodithiophene‐alt‐fluorobenzotriazole copolymer (J51) and nonfullerene material 3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d : 2′,3′‐d′]‐s‐indaceno[1,2‐b : 5,6‐b′]dithiophene (ITIC) as the donor and acceptor to study photoinduced intermolecular charge transfer (PICT) and FRET in organic solar cells. Note that J51 and ITIC are two of the best materials for organic solar cells, because they have strong FRET effects in the red region in Figure 4 because of the overlap between J51 and ITIC in the region from 500 to 600 nm …”