PbS nanocrystal solar cells with high efficiency and fill factor

We report on the fabrication of efficient PbS solar cells, showing power conversion efficiencies approaching 4% and fill factors of 60% under AM1.5 illumination. The effect of the size of two different nanocrystals (NCs) on the performance and key parameters of the devices are discussed together with peculiar features of device functioning. The results prove that the devices are not under space-charge limitation and the device performance is influenced by charge trapping which is dependent on the size of the NCs