Systematic review of molybdenum disulfide for solar cell applications: Properties, mechanism and application

Molybdenum disulfide (MoS2) has received much interest due to its revolutionary development and advantageous properties; particularly in its configurable bandgap that can transit from indirect to direct as the phase changes from the bulk form into the monolayer. MoS2 has found use in a range of solar cell technology as a hole transport layer (HTL) to facilitate charge separation and a blocking layer (EBL) to suppress the occurrence of recombination at the materials interface (silicon solar cells), a back contact at the interface between CdTe and Au, resulting in the reduction of charge carrier recombination thus improving hole extraction/collection at the back contact (CdTe solar cells), a hole extraction layer (HEL) in organic solar cells, a counter electrode (CE) by replacing classical platinum (Pt) in dye-sensitized solar cells (DSSC) and as a HTL instead of conventional materials such as PTAA, spiro-OMeTAD, and PEDOT:PSS in perovskite solar cells. The integration of MoS2 with other materials within a specific solar cell's architecture can negatively impact device performance. Therefore, this review identifies gaps and issues of using MoS2 in multiple types of solar cells in detail, alongside its highest performance use in every application.