Boosting the current density in inverted Schottky PbS quantum dot solar cells with conjugated electrolyte

•Inverted and normal quantum dot solar cells have been fabricated.•Non-conjugated PEI and conjugated PFN electrolytes have been examined.•In the inverted solar cells, the electrolyte suppresses Fermi level pinning.•PEI electrolyte results in higher open-circuit voltages.•PFN electrolyte enhances short-circuit current-density. Herein, we correlate the chemical structure of the electrolyte with the performance of inverted Schottky quantum dot (QD) solar cells (SCs) having a structure of FTO/electrolyte/p-type PbS QDs/MoOx/Au-Ag. QDSCs of polyethyleneimine (PEI) or poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-1,4-phenylene] (PFN) were fabricated for comparison. The open-circuit voltage (VOC) of QDSCs scaled with the workfunction of electrolyte – modified fluorine-doped tin oxide (FTO). Conjugated PFN electrolyte resulted in lower VOC but it boosted the current density (JSC) of QDSCs by lowering the interfacial potential barrier at FTO-PbS QDs contact.