Hybrid solar cells with in-situ prepared inorganic nanoparticles/polymer bulk heterojunction films

Lead sulfide (PbS) nanoparticles were generated by the in-situ reaction of lead chloride (II) and sulfur in the presence of poly (3-hexylthiophene) (P3HT) dissolved in the co-solvents. Three different reaction times were used to examine the effect of the PbS reaction conditions. The in-situ generated PbS nanoparticles in the P3HT matrix were spherical with a diameter of 15~25 nm. The P3HT:PbS composite materials were mixed with a soluble fullerene derivative ([6,6]-phenyl-C61-butyric acid methyl ester-PCBM) for the fabrication of hybrid solar cells. The hybrid (P3HT:PCBM:PbS) solar cells exhibited similar performance to each other, but their performance was better than the control (P3HT:PCBM) solar cells. In particular, the optimized hybrid solar cells showed ca. 14% improved power conversion efficiency due to the larger increase in short circuit current density (~30%). This improvement was attributed to the PbS nanoparticles acting as electron acceptors and a minor contribution from scattering effect.