Medium effect on Cd3P2 quantum dots photoluminescence and addition of Pt nanoparticles: Inner filter effect and screening phenomena

The formation of complex nanostructures combining quantum dots (QDs) and metallic nanoparticles (NPs) opens new perspectives to study and control energy transfer between them, provided that all the phenomena (reabsorption, screening and quenching effect) potentially affecting the photoluminescence (PL) of QDs could be identified and differentiated. First, dilution effect is studied on Cd3P2 QDs and Cd3P2@ZnS core-shell QDs solutions. The full width at half maximum, the intensity and the emission wavelength are concentration-dependent, while the decay time of PL remains constant in the conditions of measurement. These effects are shown to be fully consistent with the so-called Inner Filter Effect. The addition of Pt NPs to the QD solution causes a clear decrease of the PL intensity which could be attributed to a screening of the emission of QDs by Pt NPs instead of a possible quenching due to an interaction between the two kinds of particles. Potential bias and experimental pitfalls are highlighted to avoid misleading PL interpretations.