Dye-sensitized CdSe quantum dot hybrid materials: A new approach for optical patterning

Abstract

In this work, CdSe based quantum dots (QD) are functionalized with β tetraaminophthalocyanine dye molecules to create a functional organic-inorganic semiconductor hybrid material. This process is optimized to achieve a solution-processable material, allowing for the controlled preparation of highly homogenous QD films. The dual nature of the material leads to two individually addressable optical resonances, which are exploited in an optical read/ optical write process, creating complex optical patterns. During this process, a positive and negative fluorescence contrast are created depending on the employed excitation wavelength. This is enabled by a fluorescence enhancement of the quantum dot under excitation, in conjunction with a fluorescence bleaching of the organic dye under ambient excitation conditions. The result of the patterning process is strongly dependent on the excitation wavelength used during writing and read out of the pattern, allowing for the use of both positive and negative fluorescence contrast simultaneously depending on the wavelength. Further investigations reveal that the presence of the organic dye not only enables negative optical patterning, but also enhances the contrast during positive patterning. We show a new approach to functionalize inorganic semiconductor QDs with functional organic molecules and highlight the possibilities arising from this combination.