Polymer/silicon QDs: non-toxic, transparent and tuneable
Following two distinct preparation methods, the researchers obtained a hybrid composite of silicon nanocrystals (SiNCs) dispersed and encapsulated into poly-methylmethacrylate (PMMA), combining the good SiNC optical response and solid bulk of the PMMA. The transparent and stable bulk nanocomposites exhibited absolute quantum yields ranging from 30 to 40%.
What’s more, the researchers demonstrated that the bulk emission of these solid blocks (under illumination of a 365nm UV lamp) could be easily tuned through one of the preparation steps, by carefully controlling the final size of the SiNCs encapsulated within the solid PMMA matrix. Blue, yellow, orange and red samples are featured in a paper “Photostable Polymer/Si Nanocrystal Bulk Hybrids with Tunable Photoluminescence” they recently published in the ACS Photonics journal.
under ambient light and (bottom) 365nm UV lamp
illumination. The leftmost block is a reference pure
PMMA sample without QDs.
The PMMA/SiNC hybrid samples were further analysed under scanning electron microscopy (SEM), showing a non-porous uniform PMMA structure that truly passivated and protected the SiNC quantum dots from environmental factors. One interesting property of this bulk composite material is that it is transparent and colourless under ambient light, which could make them an attractive proposition for thin displays designed to be transparent when in the off-state.
“The motivation behind this work is light conversion applications, such as LEDs and displays”, wrote us the paper’s corresponding author, Dr. Ilya Sychugov, associate professor of materials physics at Kista-Stockholm’s Royal Institute of Technology.
“The advantage of Si QDs in comparison with Cd- or In-based ones is their non-toxicity, as well as material abundance. Now we are working on improving nanocomposite quantum yields and on a better control of the emission spectrum”.
Related articles:
Quantum dots shrink on-chip lasers to 1μm
Superfast light source made from quantum dots
Quantum dots deep into hybrid LEDs
Quantum dots taking over OLED at Samsung
Organic QD startup shows 55-inch display
If you enjoyed this article, you will like the following ones: don't miss them by subscribing to :
