Pyrazine-incorporating panchromatic sensitizers for dye sensitized solar cells under one sun and dim lightElectronic supplementary information (ESI) available: It includes the synthesis procedures, 1H NMR spectra, 13C NMR spectra, mass spectra, details of theoretical calculations and all necessary figures and tables of the new compounds. See DOI: 10.1039/c8ta04774j

New D-A′-π-A type (D = electron donor, A′ = auxiliary acceptor, π = π-conjugated bridge, and A = electron acceptor/anchor) sensitizers with two bis(alkoxy)phenyl substituents incorporating thieno[3,4- b ]pyrazines ( TP ) or a benzo[3,4- b ]pyrazine ( BP ) entity as the auxiliary acceptor have been synthesized for application in dye-sensitized solar cells (DSSCs). Under 1 sun illumination, the DSSCs fabricated from the two BP dyes with a co-adsorbent have efficiencies of 8.39% and 9.03%, respectively. The latter surpasses that of the standard N719 dye (8.87%). Under dim light conditions MD7 exhibited a power conversion efficiency of 18.95% and 27.17% under 300 lux and 6000 lux irradiance, respectively. DSSCs fabricated from benzo[3,4- b ]pyrazine-based metal-free sensitizers have efficiencies of 9.03% under 1 sun and 18.95% under 300 lux irradiance.