The photoluminescence (PL) emission of colloidal PbSe/CdSe core/shell quantum dots was systematically studied across interdot distances ranging from 7 to 240 nm, achieved by varying the concentration of the solution. A significant enhancement in valley splitting was observed when the distance L decreased below 50 nm, even though the electron and hole wave functions of neighboring QDs remained spatially separated. This effect occurred simultaneously with a redshift in PL emission due to Forster resonance energy transfer (FRET), which became detectable at L ≈ 55 nm—substantially larger than the FRET onset observed in CdSe QDs. The extended FRET range indicates a significantly larger Forster distance (R₀) for PbSe QDs, attributed to enhanced spectral overlap and strong dipole-dipole coupling.3,3′-Sulfonyldianiline supplier Crucially, the region exhibiting enhanced valley splitting precisely coincides with the active FRET regime, suggesting that the same electronic coupling responsible for energy transfer may also mediate intervalley interaction.Sanfetrinem Immunology/Inflammation Spectral analysis through Gaussian deconvolution revealed two distinct emission peaks corresponding to the split 1Se–1Sh excitonic states.PMID:34863788 For PbSe cores of 5.2 nm diameter, the energy separation increased from 38 meV at L = 42 nm to 73 meV at L = 8 nm; for smaller 4.3 nm cores, it rose from 50 meV to 77 meV as L decreased. These changes occurred without any modification in QD size or shape, confirming that the tuning is driven by proximity-induced interactions rather than intrinsic structural variation. The observation contradicts conventional FRET expectations: while FRET typically reduces the contribution of smaller QDs and should suppress splitting, here splitting increases. This implies an emergent collective mechanism, likely involving long-range coherent coupling between QDs mediated by the dielectric environment and dipole interactions. This work demonstrates a novel, field-free method to control valley splitting in PbSe quantum dots by simply adjusting interdot distance. By tuning concentration, one can dynamically modulate the energy gap between valley-split states, enabling precise engineering of optical and electronic properties. This approach offers a powerful platform for valleytronic devices, where valley degrees of freedom are used for information encoding. The findings highlight the role of interdot coupling beyond energy transfer, revealing new physical phenomena in nanoscale assemblies. Such tunability enables the design of responsive materials for applications in tunable emitters, sensors, and quantum technologies.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com