The use of fluorescent semiconductor nanocrystals for ink-jet printing applications is gaining a lot of interest in the last few years. Their unique optical features that are characterized by wide absorption spectrum accompanied by a sharp and narrow emission spectrum, along with their optical and chemical stability, offer interesting advantages for their implementation in different technologies
Although the use of fluorescent spherical semiconductor nanocrystals (quantum dots) is well established in the literature with possible applications in the field of solar cells, electronic devices, biosensing and biomarking, there are no reports for the use of fluorescent nanorods (quantum rods) in ink-jetting applications. Fluorescent nanorods are outstanding candidates for fluorescent inks, due to their relatively low self-absorption, the robust synthesis of mono-dispersed nanocrystals, their high QYs and their intrinsic emission polarization properties.
We report here on the development of dispersions and ink formulations containing CdSe/CdS seeded nanorods. The nanorods are stabilized by polymeric dispersing agents. The advantages of seeded nanorods over quantum dots in inks were examined by conducting a thorough investigation of the optical properties of both structures used in the ink-jet printing. The characteristics of nanorods and quantum dots inkjet printed patterns were compared regarding their quantum yield, fluorescence and more. Seeded nanorods ink formulations show a good dispersion, and are stable both chemically and optically over a long period of time. We show an optimal multi-layer printing of fluorescent inks with high fluorescence quantum yield and a full coverage of the substrates. Using a similar method of production, it is possible to create a wide range of inks that share the same characteristics but produce various colors. These inks are applicable for diverse applications such as signage and RGB displays.
shay.shemesh@mail.huji.ac.il
