1 research outputs found
Effects of Direct Solvent-Quantum Dot Interaction on the Optical Properties of Colloidal Monolayer WS<sub>2</sub> Quantum Dots
Because of the absence
of native dangling bonds on the surface
of the layered transition metal dichalcogenides (TMDCs), the surface
of colloidal quantum dots (QDs) of TMDCs is exposed directly to the
solvent environment. Therefore, the optical and electronic properties
of TMDCS QDs are expected to have stronger influence from the solvent
than usual surface-passivated QDs due to more direct solvent-QD interaction.
Study of such solvent effect has been difficult in colloidal QDs of
TMDC due to the large spectroscopic heterogeneity resulting from the
heterogeneity of the lateral size or (and) thickness in ensemble.
Here, we developed a new synthesis procedure producing the highly
uniform colloidal monolayer WS<sub>2</sub> QDs exhibiting well-defined
photoluminescence (PL) spectrum free from ensemble heterogeneity.
Using these newly synthesized monolayer WS<sub>2</sub> QDs, we observed
the strong influence of the aromatic solvents on the PL energy and
intensity of monolayer WS<sub>2</sub> QD beyond the simple dielectric
screening effect, which is considered to result from the direct electronic
interaction between the valence band of the QDs and molecular orbital
of the solvent. We also observed the large effect of stacking/separation
equilibrium on the PL spectrum dictated by the balance between inter
QD and QD-solvent interactions. The new capability to probe the effect
of the solvent molecules on the optical properties of colloidal TMDC
QDs will be valuable for their applications in various liquid surrounding
environments