A NIR absorbing squaraine dye has been synthesized as a sensitizer for use in dye-sensitized solar cells (DSCs). Following computational calculations, a benz[cd]indole moiety was selected as an electron-rich heterocyclic component and condensed with indole-based emisquaraine bearing a carboxyl group, as an anchor for their immobilization on TiO2, to obtain an unsymmetrical squaraine with extended absorption due to its extensive π conjugation. The cells based on this dye exhibited a spectral response in the near-infrared region over 750nm in addition to the visible region with a light absorption edge at 900nm. The cells showed 1.1% efficiency and Incident Photon Current Efficiency (IPCE) of 36% at 800nm.
Bibliographical noteFunding Information:
CM and C.Benzi acknowledge financial support by Innovasol EU project ( 227057-2 ), JP, CB and NB acknowledge financial support by DSSCX project ( PRIN 2010-2011 , 20104XET32 ) from Ministero dell'Istruzione, dell'Università e della Ricerca . NB thanks MIUR for partial funding her research grant. SM and AA acknowledge support from the Imperial College UROP Bursary and the Alan Howard Scholarship for Energy Futures. We thank Dr. Davide Di Censo for electrochemical measurements and fruitful discussion and Ms. Ada Ferri for her valuable help.
- DFT calculation
- Dye-sensitized solar cell
- NIR squaraine