We investigate the effect of nanoparticles–nanospheres and nanorods–inserted in the poly(3-hexylthiophene) (P3HT) matrix of inverted hybrid solar cells. X-ray diffraction, high-resolution transmission electron microscopy, small-angle x-ray scattering, photoluminescence, and photoelectrochemical experiments were employed to investigate the structure, morphology, and photoactivity of nanoparticles modified with 2-thiopheneacetic acid, mixed or not with P3HT. Both nanospheres and nanorods presented a good dispersion in the polymer matrix. The incorporation of nanospheres and nanorods has improved the photocurrent generation, and devices with efficiency values up to 1.35% were obtained. Our results reveal that the nanoscale morphology enables an enhanced interfacial area for exciton dissociation. In particular, the nanospheres contribute with their high specific area, and the nanorods contribute with their high aspect ratio.