Efficient organic DSSC sensitizers bearing an electron-deficient pyrimidine as an effective π-spacer

A series of new push–pull organic dyes incorporating electron-deficient pyrimidine as the π-spacer have been synthesized, characterized, and used as the sensitizers for dye-sensitized solar cells (DSSCs). In comparison with the model compound M-TP, which adopts phenylene as the π-spacer, the tailor-made dyes display enhanced spectral responses in the red portion of the solar spectrum. Through the introduction of two hexyloxy chains on the diphenylthienylamine donor, the DSSC employing dye OHexDPTP exhibited high power conversion efficiency up to 7.64% under AM1.5G irradiation.