5 BODIPY Dyes and Their Analogues
191
2016)-fused BOPHY dyes have been reported, and these fused derivatives show more
redshifted absorption and fluorescence maxima. BOPHY dyes have been applied to
electron donor material for bulk heterojunction (BHJ) solar cells (Mirloup et al.
2015), pH sensors (Jiang et al. 2015), and triplet–triplet annihilation upconversion
(Zhang and Zhao 2016).
In carbazole-based BODIPY dimer, the unsymmetrical derivative (R
1
=
t Bu, R
2
= Mes: F max = 609 nm, Φ f = 0.110) tends to show higher Φ f than the symmetrical
derivative (189: F max = 588 nm, Φ f = 0.064) in the solid-state (Fig. 5.68b) (Maeda
et al. 2017).
A double B ← N bridged bipyridyl (BNBP) shows intense fluorescence
(Fig. 5.68c) (Dou et al. 2016). BNBP is an electron-deficient building block for
polymer electron acceptors. The B ← N bridging units endow BNBP with a fixed
planar configuration and low-lying LUMO/HOMO energy levels. The polymer based
on BNBP and thiophene units (P-BNBP-T) exhibits high electron mobility, lowlying LUMO/HOMO energy levels, and strong absorbance in the visible region,
which is desirable for polymer electron acceptors. Preliminarily, all-polymer solar
cell (all-PSC) devices with P-BNBP-T as the electron acceptor and PTB7 as the
electron donor exhibit a PCE of 3.38%. All-PSC devices with polymers based on
BNBP and 4,4-difluoro-4H-cyclopenta[2,1-b:3,4-b
]dithiophene (fCDT) units (PBNBP- fCDT) as electron acceptors show a PCE of 3.83% (Zhao et al. 2017a). By
changing the substituents from fluorine atoms to phenyl groups, the λ max and F max are
redshifted and the electron affinities are degraded due to the electron-withdrawing
ability of the fluorine atoms (E ox, onset vs. Fc/Fc
+ : 190: 0.38 V, 191: 0.60 V, 192:
0.83 V, E red, onset vs. Fc/Fc
+ : 190: −1.87 V, 191: −1.72 V, 192: −1.61 V) (Wang et al.
2018b).
Bisbron complex 193 shows well separated two reductive and two oxidative
electron transfer processes (Fig. 5.68d) (Zhu et al. 2018). Spectroelectrochemical
measurements reveal multicolour electrochromism with excellent recyclability. The
radical cation and dication of 193 show absorption at 1180 nm corresponding to
HOMO-β to LUMO-β transition of the delocalized radical cation and multiple
absorption bands covering a broad visible light region, respectively. The radical
anion of 193 shows a highly intensive absorption at 677 nm and a weak absorption at
ca. 940 nm, corresponding to the HOMO-1-α to LUMO-α and HOMO-β to LUMOβ transitions of the radical anion, respectively. The dianion of 193 shows absorption
at 544 nm, corresponding to the HOMO to LOMO transition.
B ← N-containing azaacene 194 shows λ max at 686 nm with an ε value of 113,000
(Fig. 5.69a) (Min et al. 2018). The introduction of B ← N units into azaacene
leads to significant perturbations of the electronic structure, that is, unique LUMO
delocalized over the entire acene skeleton, decreased aromaticity of the B ← Nadjacent rings, low-lying LUMO energy levels, and high electron affinities. Solutionprocessed OFET devices based on 194 show unipolar n-type characteristics with an
electron mobility of up to 0.21 cm
2 V
−1 s
−1 .
BOPPY dyes which are unsymmetrical bis(BF 2 ) dyes containing both pyrrole
and N-heteroarene derivatives are prepared via a simple one-pot procedure
191
2016)-fused BOPHY dyes have been reported, and these fused derivatives show more
redshifted absorption and fluorescence maxima. BOPHY dyes have been applied to
electron donor material for bulk heterojunction (BHJ) solar cells (Mirloup et al.
2015), pH sensors (Jiang et al. 2015), and triplet–triplet annihilation upconversion
(Zhang and Zhao 2016).
In carbazole-based BODIPY dimer, the unsymmetrical derivative (R
1
=
t Bu, R
2
= Mes: F max = 609 nm, Φ f = 0.110) tends to show higher Φ f than the symmetrical
derivative (189: F max = 588 nm, Φ f = 0.064) in the solid-state (Fig. 5.68b) (Maeda
et al. 2017).
A double B ← N bridged bipyridyl (BNBP) shows intense fluorescence
(Fig. 5.68c) (Dou et al. 2016). BNBP is an electron-deficient building block for
polymer electron acceptors. The B ← N bridging units endow BNBP with a fixed
planar configuration and low-lying LUMO/HOMO energy levels. The polymer based
on BNBP and thiophene units (P-BNBP-T) exhibits high electron mobility, lowlying LUMO/HOMO energy levels, and strong absorbance in the visible region,
which is desirable for polymer electron acceptors. Preliminarily, all-polymer solar
cell (all-PSC) devices with P-BNBP-T as the electron acceptor and PTB7 as the
electron donor exhibit a PCE of 3.38%. All-PSC devices with polymers based on
BNBP and 4,4-difluoro-4H-cyclopenta[2,1-b:3,4-b
]dithiophene (fCDT) units (PBNBP- fCDT) as electron acceptors show a PCE of 3.83% (Zhao et al. 2017a). By
changing the substituents from fluorine atoms to phenyl groups, the λ max and F max are
redshifted and the electron affinities are degraded due to the electron-withdrawing
ability of the fluorine atoms (E ox, onset vs. Fc/Fc
+ : 190: 0.38 V, 191: 0.60 V, 192:
0.83 V, E red, onset vs. Fc/Fc
+ : 190: −1.87 V, 191: −1.72 V, 192: −1.61 V) (Wang et al.
2018b).
Bisbron complex 193 shows well separated two reductive and two oxidative
electron transfer processes (Fig. 5.68d) (Zhu et al. 2018). Spectroelectrochemical
measurements reveal multicolour electrochromism with excellent recyclability. The
radical cation and dication of 193 show absorption at 1180 nm corresponding to
HOMO-β to LUMO-β transition of the delocalized radical cation and multiple
absorption bands covering a broad visible light region, respectively. The radical
anion of 193 shows a highly intensive absorption at 677 nm and a weak absorption at
ca. 940 nm, corresponding to the HOMO-1-α to LUMO-α and HOMO-β to LUMOβ transitions of the radical anion, respectively. The dianion of 193 shows absorption
at 544 nm, corresponding to the HOMO to LOMO transition.
B ← N-containing azaacene 194 shows λ max at 686 nm with an ε value of 113,000
(Fig. 5.69a) (Min et al. 2018). The introduction of B ← N units into azaacene
leads to significant perturbations of the electronic structure, that is, unique LUMO
delocalized over the entire acene skeleton, decreased aromaticity of the B ← Nadjacent rings, low-lying LUMO energy levels, and high electron affinities. Solutionprocessed OFET devices based on 194 show unipolar n-type characteristics with an
electron mobility of up to 0.21 cm
2 V
−1 s
−1 .
BOPPY dyes which are unsymmetrical bis(BF 2 ) dyes containing both pyrrole
and N-heteroarene derivatives are prepared via a simple one-pot procedure