The effect of manganese in a CdS/PbS colloidal quantum dot sensitized TiO2 solar cell to enhance its efficiency

Herein, we demonstrate for the first time the impact of Mn on PbS and CdS using a simple successive ion layer adsorption and reaction (SILAR) technique on TiO2. The CdS passivation layer over PbS can reduce the recombination of photo-injected electrons with the electrolyte and enhance the overall performance and stability of quantum dot sensitized solar cells (QDSSCs). The doping of Mn has a drastic impact on the host material (PbS/CdS) and can create new energy states that can delay the exciton recombination time and can allow charge separation. The surface roughness and morphology of the PbS/Mn-CdS nanoparticles can be observed from atomic force microscopy images. The performance of the QDSSCs was examined in detail using a polysulfide electrolyte with a copper sulfide (CuS) counter electrode. Under illumination of one sun (AM 1.5 G, 100 mW cm−2), the TiO2/PbS/Mn-CdS QDSSCs exhibits a power conversion efficiency (η) of 3.55%.