Enhanced performance of hybrid solar cells using carboxylic acid-functionalized graphene oxide supported TiO2 nanorod composites

We have successfully developed the carboxylic acid-functionalized graphene oxide-TiO2 nanorod composites (GO-COOH–TiO2) by a facile ligand exchange process in tetrahydrofuran. TiO2 nanorods were uniformly anchored on the surface of carboxylic acid functionalized graphene oxide (GO-COOH) sheet. The insulated oleic acid ligands are completely cleaned from the surface of TiO2 nanorods. The GO-COOH–TiO2 composite can effectively quench the photoluminescence of poly (3-hexylthiophene) (P3HT) and used as a good acceptor materials in hybrid solar cells. The P3HT/GO-COOH–TiO2 hybrid solar cell shows significantly improved property than P3HT/oleic acid capped TiO2 solar cell. Our work paved a new way to get well assembled TiO2 nanorod without insulated organic ligands for the photovoltaic application.

► High quality GO-COOH–TiO2 nanorod composite was prepared.
► TiO2 nanorod are attached on GO-COOH sheet uniformly.
► GO-COOH–TiO2 can strongly quench the PL of P3HT.
► Significantly increased efficiency can be obtained with P3HT/GO-COOH–TiO2 blends than P3HT/oleic acid–TiO2.