A new study involving researchers from the University of Illinois at Chicago has become an important milestone in the synthesis of multifunctional photonic nanomaterials. In an article published in the journal Nano Letters, report the synthesis of semiconductor “giant” core-shell quantum dots with record lifetimes. In addition, the service life can be adjusted by making a simple change in the internal structure of the material.
A group that includes Princeton University and Pennsylvania State University has demonstrated a new concept of structure properties that enable the spatial localization of electrons or holes in a core/shell heterostructure by tuning the kinetic energy of a charge carrier on a parabolic potential energy surface.
According to UIC chemist Preston Snee, this separation of charge carriers results in longer emission lifetimes and sustained emission at the individual nanoparticle level.
“These properties create new applications for optics, facilitate new approaches such as time-limited single particle imaging, and pave the way for the development of other new advanced materials,” said Snee, UIC professor of chemistry and senior co-author. of your study.
Sney and the study’s first author, Marcel Palmay, a UIC research associate in chemistry, teamed up with Hau Yang of Princeton and others to excite a quantum dot particle with light to put it in an “exciton” state. An exciton is an electron/hole charge pair, and in new materials the electron moves from the center to the shell where it lingers for more than 500 nanoseconds, a record for such nanomaterials.
“As emitting materials, quantum dots hold promise for more energy-efficient images and can be used as fluorescent probes for biomedical research due to their highly reliable optical properties. They have 10-100 times greater absorption than organic dyes and are nearly immune to light bleaching, so Samsung They are used in ‘s new QLED TV,” they write.
According to the researchers, these new particles hold great potential for fundamental biological discoveries. The quantum dots presented in their paper emit at a red wavelength that minimizes scattering, while its long lifetime allows for bioimaging with less background noise. At the level of a single particle, new quantum dots are continuously emitted so the scientist can tag cancer-associated proteins and monitor biological dynamics without losing the signal, which is now a common problem for this type of research.
In future research, the group plans to demonstrate that these materials make good components for optical devices such as micron-sized lasers.
Source: Port Altele
