Photoinduced energy and charge transfer in a p-phenylene-linked dyad of boron dipyrromethene and monostyryl boron dipyrromethene

Abstract

Boron dipyrromethenes (BDPs) are excellent building blocks for design of artificial light harvesting and charge separation systems. In the present work, we report the results of photophysical studies of a novel dyad, in which a BDP and a mono-styryl BDP (MSBDP) are covalently linked to each other at the meso-position via a p-phenylene unit. It was found that the photophysical properties of the dyad dissolved in polar as well as nonpolar solvents are strongly affected by two different types of interactions between the BDP and MSBDP parts, namely excitation energy transfer and photoinduced electron transfer. The first process delivers the excitation energy to the first excited singlet state of the MSBDP-part upon excitation of the BDP unit. The direct or indirect (via excitation energy transfer) population of the first excited singlet state of the MSBDP moiety is followed by hole transfer to generate the charge-separated state. In non-polar toluene, the probability of charge separation is low, whereas in polar acetonitrile the charge separation quantum yield is close to unity, resulting in strong quenching of the MSBDP fluorescence.

Design, synthesis and photophysical studies of dipyrromethene-based materials: insights into their applications in organic photovoltaic devices

“…The Ziessel and Harriman groups presented an interesting study on spirofluorene-bridged BODIPY dyads (197)(198)(199)(200)(201); Fig. 54).…”

“…This work was a follow-up of their photophysical study of the BODIPY-MSBDP dyad alone. 199 Harvey et al recently prepared another system where the BODIPY chromophore was used to bridge two porphyrins. 200 In that case, a strategy of derivatization at the boron center was used to prepare metal-free and Zn II metalated B,B-diporphyrinbenzyloxy-BODIPY derivatives (341 and 342, respectively; Fig.…”

meso-2′-Linked porphyrin–BODIPY hybrids: synthesis and efficient excitation energy transfer

“…1-16 Compared with their 20 extremely strong absorption in the blue and red regions, porphyrin-based artificial antennas generally lack a significant absorption in the visible spectral region. To provide a better match with the solar spectrum, chromophores with complementary absorption, such as carotenoids, 17,18 25 phthalocyanines, [19][20][21][22][23][24] and BODIPYs, have been attached to the porphyrin structures. Amongst those, BODIPYs, which have intense absorption in the range of 450−550 nm, have been widely integrated into hybrids of porphyrins via either covalent bond or non-covalent bond.…”

Energy transfer properties of a novel boron dipyrromethene–perylenediimide donor–acceptor dyad

“…In photosynthetic organisms the electromagnetic energy captured by chromophore-rich antenna proteins is delivered via efficient EET process to a reaction centre where a multi-step electron transfer reaction occurs, leading to conversion of the absorbed photon energy into chemical energy. [2][3][4][5][13][14][15][16][17][18] Among the different chromophores, boron dipyrromethenes (BDP) and perylenediimides (PDI) are of particular interest. [9][10][11][12] A great variaty of donor-acceptor systems with different combination of chromophores have been reported in the literature with the aim of enhancing their energy transfer efficiency and facilitating subsequent use in generation of chemical and electrical potential energies.…”

“…[9][10][11][12] A great variety of donor-acceptor systems with different combination of chromophores have been reported in the literature with the aim of enhancing their energy transfer efficiency and facilitating subsequent use in generation of chemical and electrical potential energies. [2][3][4][5][13][14][15][16][17][18] Among the different chromophores, boron dipyrromethenes (BDP) and perylenediimides (PDI) are of particular interest. The former exhibit large extinction coef-cients around 500 nm, high uorescence quantum yields, reasonably long excited singlet state lifetimes, good solubility in many solvents and excellent photostability.…”