Photoluminescence in MoS2 Multilayers with Functional Polyelectrolyte Nanospacing

Abstract

Photoluminescence phenomenon in multilayers of molybdenum disulfide (MoS2) spaced by nano-thick polyelectrolyte layers are demonstrated on behalf of various transition metal dichalcogenides. Using facile method of layer-by-layer (LbL) assembly, negative charged MoS2 sheet and positive charged polymeric layers are sequentially stacked on various substrates. In this structure, individual MoS2 monolayers are not only effectively screened from interlayer coupling but also p-doped by functional polymeric layers. The Raman analysis demonstrates that MoS2 nanosheets separated by polymeric trilayers display much larger increase in photoluminescence (PL) as the number of layers is increased. Furthermore, it was also found that the enhanced PL has been correlated to the ratio of excitons to trions with type of polymeric spacers. Because uniform heterogeneous interfaces can be formed between various transition metal dichalcogenides and other soft materials, we expect that the result will be a trigger to fabricate hetero vertical architecture with other 2D analogues and will offer potential electronic and optoelectronic applications.