A Quantum Dot Mini Spectrometer | Chemical & Engineering News
Volume 93 Issue 27 | p. 41 | Concentrates
Issue Date: July 6, 2015

A Quantum Dot Mini Spectrometer

Spectroscopy: A device made from an array of 195 filters covers a 300-nm range and resolves peaks separated by 2 nm
Department: Science & Technology
Keywords: Spectrometer, spectroscopy, quantum dots
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This quantum dot spectrometer is the size of the sensors that digital cameras use to collect images.
Credit: Jie Bao
Photograph of colloidal quantum spectrometer in digital camera housing.
 
This quantum dot spectrometer is the size of the sensors that digital cameras use to collect images.
Credit: Jie Bao
[+]Enlarge
A quantum dot spectrometer chip is made by printing quantum dot inks on the surface of a detector array, as shown in this rendering.
Credit: Mary O’Reilly
Printing a colloidal quantum dot spectrometer.
 
A quantum dot spectrometer chip is made by printing quantum dot inks on the surface of a detector array, as shown in this rendering.
Credit: Mary O’Reilly

Miniature spectrometers could make it easier to perform spectroscopy on the go. Jie Bao of Tsinghua University, in Beijing, and Moungi G. Bawendi of MIT have now developed a new way of creating one from an array of 195 filters made by printing different colloidal quantum dot inks on a microchip (Nature 2015, DOI: 10.1038/nature14576). The spectrometer, which covers the wavelength range of 390 to 690 nm, is the size of the charge-coupled device (CCD) sensor in a digital camera. Because each filter transmits light differently at different wavelengths, the intensity of light transmitted through the set can be combined to reconstruct the spectrum. Bao and Bawendi used their spectrometer to measure spectra generated by a white light source and a set of optical filters and to measure the emission spectra of fluorescent colloidal quantum dots. The researchers were able to resolve spectral peaks separated by 2 to 3 nm. They say the spectral range and resolution could be further improved by using additional quantum dot filters.

 
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