High efficiency double heterojunction polymer photovoltaic cells using highly ordered TiO2 nanotube arrays

Abstract
Vertically oriented Ti O 2 nanotube arrays formed by anodization offer a highly ordered material architecture for efficient charge generation and collection in photoelectrochemical devices. A blend of regioregular poly(3-hexylthiophene) and a methanofullerene (phenyl C 71 -butyric acid methyl ester) was infiltrated into transparent Ti O 2 nanotube films. The heterojunction poly(3-hexylthiophene) (P3HT)-([6,6]-phenyl- C 71 -butyric acid methyl ester) and P3HT- Ti O 2 interfaces both result in charge separation. The resulting solid state solar cells show a short-circuit current density of 12.4 mA ∕ cm 2 , 641 mV open circuit potential, and a 0.51 fill factor, yielding power conversion efficiencies of 4.1% under AM 1.5 sun.