Materials Science

From solution to a solid bright idea

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Science  03 Jul 2015:
Vol. 349, Issue 6243, pp. 43
DOI: 10.1126/science.349.6243.43-g

Semiconducting quantum dots are ideal for down-converting light, so that a single blue source can be partly changed into other colors to give an overall white emission. Hanson et al. note that the conversion efficiency seen for quantum dots in solution is rarely matched when they are put into solid-state devices. This is particularly true for the red part of the spectrum, for which the best converters depend on expensive rare earth materials. Using low-cost materials, they grew CdSe/CdS core/shell particles so that the particles were mostly shell material. Conversion efficiencies in solid-state devices approached unity. At high driving currents, thermal quenching was a problem but was partly solved by adding a spacer between the light source and quantum dot layer.

ACS Appl. Mat. Inter. 10.1021/acsami.5b02818 (2015).

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