Colloidal quantum dots are solution-based nanocrystals prized for their unique light-harvesting abilities. They can illuminate, create color, harness solar energy and function as semiconductors. These well-studied systems have become so efficient, the photoluminescence quantum yield (PLQY) can approach unity, meaning for every photon absorbed by the solution, one photon is re-emitted in an almost perfect ratio of 1-to-1. But for these state-of-the-art quantum dots to be utilized outside the laboratory in the next generation of LEDs, screens and semiconductors, we need reliable, accurate and precise methods for certifying claims of unity. When a photon hits a quantum dot, that photon is either re-emitted as light or it dissipates as heat. Typically, PLQY is captured by quantifying light, but this kind of data can be convoluted and the methods for acquiring it can be difficult to reproduce. So scientists have simplified both the data collection and analysis by measuring heat instead.. This work allows scientists to verify the PLQY of their quantum dot solutions after synthesis and could help streamline the use of colloidal quantum dots in new technologies. This work allows scientists to verify the efficiency of their quantum dot solutions after synthesis and could help streamline the use of colloidal quantum dots in new technologies.
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Source article:
“Accurate, Precise, and Verifiable Photoluminescence Efficiency of Colloidal Quantum Dots Sols by Photothermal Threshold Quantum Yield Analysis”
Chemistry of Materials
Corresponding author: Koen Vandewal, Ph.D.
Transcript
Scientists are getting so good at making colloidal quantum dots, they’re approaching perfect efficiency, also known as unity. But to move these quantum dots into the next generation of screens and semiconductors, we need new techniques to measure efficiency on the quantum scale. When a photon hits a quantum dot, it will either be re-emitted as light or it will dissipate as heat, which is wasted energy. Currently, researchers measure efficiency by counting photons. But the results can be difficult to interpret. So scientists have developed a new method that simplifies everything by looking at that wasted heat energy instead. More efficient quantum dots will give off less heat, and that's much easier to interpret. This approach provides a standardized technique for verifying claims of unity and lets scientists quickly and directly test their quantum dot solutions in the lab, paving the way for the next generation of quantum dots to come out of the vial and into the technology we use every day.
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