Panchromatic light harvesting and record power conversion efficiency for carboxylic/cyanoacrylic Fe(ii) NHC co-sensitized FeSSCs

Abstract

Fe(II) pyridyl-NHC sensitizers bearing thienylcyanoacrylic anchoring groups (ThCA) have been designed and characterized with the aim of enhancing the metal to surface charge separation and the light harvesting window in...

Ferrous and ferric complexes with cyclometalating N-heterocyclic carbene ligands: a case of dual emission revisited

“…solar energy conversion and photoredox catalysis [5][6][7][8] or OLEDs. 9,10 Iron complexes as analogues of the archetypal ruthenium polypyridyl photosensitizers 11 have since long attracted particular interest [12][13][14][15][16][17][18][19][20] and the more recent progress with N-heterocyclic carbene (NHC) ligands [21][22][23][24][25][26][27][28] has eventually led to ferrous and ferric complexes with demonstrated excited-state electron transfer reactivity of their triplet metal-to-ligand charge transfer ( 3 MLCT) [29][30][31][32][33][34][35] and doublet ligand-to-metal charge transfer ( 2 LMCT) [36][37][38][39][40][41][42] states, respectively. Furthermore, with lifetimes up to nanoseconds and larger oscillator strengths of the spinallowed transition between the 2 LMCT and the doublet ground state, Fe(III)NHCs can also feature signicant photoluminescence quantum yields.…”

Iron-Sensitized Solar Cells (FeSSCs)

“…67 Thus, ThCA has been introduced on the complexes following Scheme 2. 4 The absorption spectra of C1, ARM12, and ARM242 chemisorbed on a 13 μm TiO 2 anode showed a strong redshift of the MLCT band with ARM12 and ARM242 that however leaves an almost transparent window between 400 and 500 nm, where, in contrast C1 strongly absorbs. Thus, to further improve the spectral sensitivity of the photoanodes, we have performed the cosensitization of C1 and ARM12 that resulted in a nice panchromatic absorption from 450 to 700 nm (Figure 10).…”

“…We have introduced the thienylcyanoacrylic moiety (ThCA) as anchoring group , that has been reported to exhibit a robust S···CN bond leading to two intramolecular charge transfers that should enhance the electron transfer . Thus, ThCA has been introduced on the complexes following Scheme …”

“…Thus, to further improve the spectral sensitivity of the photoanodes, we have performed the cosensitization of C1 and ARM12 that resulted in a nice panchromatic absorption from 450 to 700 nm (Figure 10). 4 DSSCs have been assembled, including these sensitizers. A 20 μm TiO 2 with a scattering top layer, PEDOT-based counter electrode and el3 were used.…”

Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C∧N∧C) Pincer Ligand─A Comparative Study

“…Arguably, the best approach to this end has been achieved by the introduction of strongly σ-donating ligands that destabilize the MC states in an octahedral ligand field. Hence, the introduction of N -heterocyclic carbene (NHC) ligands ,− has eventually led to ferrous and ferric complexes that show excited-state electron-transfer reactivity of their triplet metal-to-ligand charge transfer ( 3 MLCT) states − and doublet ligand-to-metal charge transfer ( 2 LMCT) states, ,− respectively. In particular, the use of two tridentate scorpionate ligands, giving a facial attachment of a pair of three NHC ligands to iron, has been shown to be advantageous.…”