Novel Metal Complexes Unit of Phenanthroline Derivative for Being Used as Auxiliary Electron Acceptor in Dye Sensitizer Molecules

Abstract

AbstractDonor‐acceptor‐π bridge‐acceptor (D−A−π−A) motif dyes are promising dye sensitizers in dye‐sensitized solar cells (DSSCs). In this study, to strengthen with‐drawing electron force of the auxiliary electron acceptors(A) in D−A−π−A motif dye sensitizers, the metal complexes unit is be used as auxiliary electron acceptor(A) instead of organic electron‐withdrawing monomer. The four polymeric metal complexes were designed, synthesized, and characterized, which used metal complexes of phenanthroline derivatives as auxiliary acceptors (A), benzodithiophene‐dithiophene derivatives (BDTT) as donors (D), and 8‐hydroxyquinoline derivatives as π‐bridges and acceptors of the dye sensitizers, and have been used for dye sensitizers. Under AM 1.5 G (100 mW cm−2), the photovoltaic test results indicated that the short‐circuit photocurrent density (Jsc) of the DSSCs based four polymeric metal complexes are 11.26, 13.68, 14.42 and 15.57 mA cm−2and power conversion efficiency (PCE) are 5.96 %, 7.83 %, 8.07 %, 9.28 % respectively. BothJscandPCEvalue of the four polymeric metal complexes increased in order. This may be due to the fact that larger radius of metal ion under the same change number can enhance the coordination bond and cause stronger electron‐withdrawing ability of auxiliary acceptor and stronger charge‐transfer ability between the donor and the acceptor, which results in higherJscand higherPCEof the polymeric complex dye sensitizer.