Scientists solve fluorescent crystal mystery

Aug. 31 (UPI) -- A pair of organic crystals, seemingly identical but grown in two different locations, fluoresce different colors -- a classic whodunit.

Thanks to a team of scientists at the University of Bristol, the case of glowing crystal has finally been solved.

Under ultraviolet light, the naturally occurring crystal karpatite shines a brilliant fluorescent blue. But when grown in the lab, karpatite fluoresces a rich green.

Researchers long assumed chemical impurities from the lab setting explained the color discrepancy, but an in-depth analysis of the crystal's internal structure suggests otherwise.

Scientists used a combination of electron microscopy, fluorescence spectroscopy and X-Ray diffraction to study the crystal's internal nanostructure. Naturally grown karpatite yields a nanoscale texture that encourages a unique photonic pathway -- a pathway that enables blue fluorescence.

The synthetic crystal growth creates a non-layered internal structure that encourages a green fluorescence.

Researchers officially closed the case of glowing crystal with a new paper, published this week in the journal Scientific Reports.

"As this study proves that color change in organic crystals can be a solid-state morphological phenomenon, we believe that our interrogative method can be applied to many other organic crystal systems to potentially uncover exotic charge transfer pathways in semiconductors, field-effect transistors and organic superconductors," Bristol chemist Simon Hall said in a news release.