Measuring local quantum yield of photoluminescence and phototransformations with laser scanning microscope

Measurement of local quantum yields for the photoluminescence of semiconductor nanocrystals (quantum dots) and photoinduced transformations of dye molecules in polymer films is demonstrated using a laser scanning microscope capable of mapping luminescence spectra and intensities of transmitted laser light. The confocal scanning microscope (Zeiss LSM710) was applied for both the induction of photochemical transformations and measurement the luminescence quantum yield values for quantum dots in different locations of a polymer film were found to differ, ostensibly depending on their aggregation. To measure photoisomerization quantum yield, the effects of scanning a tiny area of a polymer film with a focused beam on the intensities of luminescence and transmitted light were monitored.