Table 1. Optical and electrochemical properties of dyes. ^aAbsorbances of the dyes with ~2 × 10⁻⁵ M concentration in THF solution. ^bThe ground-state oxidation potential of the dyes was measured under the following conditions: electrolyte, 0.1 M tetra-n-butylammonium hexafluorophosphate in dimethylformamide; electrode, Platinum counter and reference electrodes were used with a glassy carbon working electrode. Potentials measured vs. Fc⁺/Fc were converted to NHE by addition of +0.69 V³⁹. ^cOptical transition energy, estimated from the onset of the absorption. ^dExcited-state oxidation potential energies vs. NHE estimated from the ground-state oxidation potential (E_Ox), by subtracting the bandgap (E_g^opt).

Dye	ε (M−1 cm−1) [Absmax (nm)]a	E(S+/S) (V)b	E(S−/S) (V)b	Egopt (eV)c	E(S+/S*) (V)d
DPP13	30,300 (377)/55,700 (587)	0.99	−0.98	1.85	−0.86
DPP14	31,200 (380)/57,100 (596)	0.94	−0.98	1.81	−0.87
DPP15	38,800 (374)/62,400 (600)	0.94	−0.96	1.80	−0.86
DPP17	67,000 (393)/69,000 (602)	0.98	−0.99	1.80	−0.82