Page 38 - KVIS Book

PHY03I

Fluorescent dyes from plants for lightning applications

Laphas Premcharoen, Kasin Onprasop, Kunlanit Prasopsukchokmanee
Kamnoetvidya Science Academy, Thailand
Supervisor: Adis Khetubol
Email: kunlanit19@hotmail.com

The extracted dyes from two kinds of plant, turmeric and Jasminum leaf which are
commonly found in Thailand, are investigated on their fluorescent properties. Upon
photoexcitation, a solution of turmeric extract produces green fluorescence with a
maximum intensity around 525 nm corresponding to properties of curcumin as a major
dye component; while a solution of Jasminum leaf extract produces red fluorescence
with a maximum intensity around 670 nm corresponding to properties of chlorophyll
as a major dye component. In poly(methyl methacrylate) (PMMA) film, similar
fluorescent properties are found for the Jasminum leaf extract. However, a presence of
blue shift of the fluorescent spectrum is observed for the turmeric extract in the
PMMA film compared to its solution which is possibly attributed to an aggregation of
curcumin molecules in a solid state. A mixture of both extracts in PMMA films at
different ratios evidences a tunable emission color toward white light. A blue-white
light emission with Commission Internationale d’Eclairage (CIE) chromaticity index
(0.305,0.294) is obtained at 2.5:1 molar ratio of turmeric and Jasminum leaf extracts in
a PMMA film which promises their application as a source for white light.

Keywords: Fluorescent dye, Fluorescent spectrum, Photoexcitation, Lightning
application, CIE chromaticity index