Langmuir and Langmuir–Blodgett films of quantum dots

Trioctylphosphine oxide (TOPO) capped CdSe and (CdSe)ZnS quantum dots (QDs) were prepared. The surface chemistry behavior of both QDs at the air–water interface was carefully examined by various physical measurements. Stable Langmuir films were formed for both QDs. The average limiting nanoparticle area derived from the π–A isotherms of the QDs could be used to estimate the average size of the QDs if the thickness of TOPO shell was counted. The epifluorescence image of the QDs Langmuir films revealed an aggregation in 2D during the early stage of the compression process. On the other hand, a diacetylene-peptide (PDA-Cys-Cys-Gly-OH) derivative, namely PDA-CCG, was used to modify the surface of QDs. This modification resulted in a robust and homogeneous Langmuir film, which is photopolymerizable and contains active binding sites for the binding of biomolecules.