Quantum dots has possibilities for imaging biological imaging

In a recent study, scientists at the University of Illinois Chicago made progress toward the synthesis of multipurpose photonic nanoparticles.

They describe the creation of semiconductor “giant” core-shell quantum dots with record-breaking emissive lifetimes in an article that was published in the American Chemical Society journal Nano Letters. The lives can also be adjusted by making minor changes to the material’s internal structure.

By adjusting the charge carrier’s kinetic energy on a parabolic potential energy surface, the team—which also included collaborators from Pennsylvania State University and Princeton University—proved a novel structure-property concept. This concept allows for the spatial localization of electrons or holes within a core-shell heterostructure.

Preston Snee, a chemist with the University of Illinois in Chicago, claims that this charge carrier separation causes extended radiative lifetimes and continuous emission at the single-nanoparticle level.

According to Snee, the senior co-author of the paper and an associate professor of chemistry at UIC, “these features enable new applications for optics, facilitate novel approaches like time-gated single-particle imaging, and create inroads for the creation of other new advanced materials.”

The quantum dot particle was excited with light to enter the “exciton” state by Snee and the study’s first author, Marcell Pálmai, a postdoctoral research associate in chemistry at UIC. The exciton, an electron-hole charge pair, is moved from the center to the shell in the new materials, setting a record for such nanomaterials by becoming imprisoned there for more than 500 nanoseconds.

“Due to their highly stable optical characteristics, quantum dots can be used as fluorescent probes for biomedical research in addition to holding the potential to produce more energy-efficient displays.” They are employed in the new Samsung QLED-TV since they are 10 to 100 times more absorbent than organic dyes and are essentially resistant to photobleaching.

The researchers claim that these novel particles are highly effective at uncovering underlying biological imaging principles.

The authors’ quantum dots emit at red wavelengths, which reduces scattering, and have long lifetimes, which reduce background noise in biological imaging. The new quantum dots emit constantly at the single particle level, allowing researchers to tag cancer-related proteins and monitor biological dynamics without losing track of the signal, which is currently a common issue with such investigations.

The team hopes to show that the materials are suitable building blocks for optical devices like micron-sized lasers in further research.

The following individuals from UIC, Princeton, and Pennsylvania State University, as well as Marcell Pálmai, Eun Byoel Kim, Prakash Parajuli, Kyle Tomczak, Kai Wang, Bibash Sapkota, Nan Jiang, and Robert F. Klie, are also co-authors of the study.