Regular Article

Optical and structural properties of curcuminoids extracted from Curcuma longa L. for hybrid white light diode

¹ School of Physics, Universiti Sains Malaysia, 11800 USM Penang, Malaysia

² Institute of Nano Optoelectronics Research and Technology (INOR), Universiti Sains Malaysia, 11800 USM Penang, Malaysia
³ Department of Physics, College of Science, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
⁴ Department of Nano-medicine Research, Institute for Research & Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia
⁵ School of Chemical Sciences, Universiti Sains Malaysia, 11800 USM Penang, Malaysia

^* corresponding author: e-mail: nas_tiji@yahoo.com

Received: 24 June 2018
Accepted: 1 October 2018
Published online: 16 November 2018

Abstract

In this study, curcuminoids were extracted from turmeric (Curcuma longa L.) by means of three methods, comprising the normal method, use of Soxhlet apparatus and by combining the normal method with the Soxhlet extraction approach. The limitation of stickiness in the use of curcuminoids was resolved by mixing it with silica gel. The curcuminoids used light down-conversion of UV light (390 nm) for the white light-emitting diode (WLED). The characteristics of the white light chromaticity were controlled by changing the current and concentration of the curcuminoids. The chromaticity coordinates (CIE) and correlated color temperature (CCT) were measured for different applied currents (20, 60 and 100 mA) and weights (25, 35 and 50 mg) of curcuminoids. It was observed from the concentration of phosphor that the combination of the normal and Soxhlet apparatus methods is most effective extraction approach. The results showed that increasing the concentration of phosphor significantly and remarkably increased the value of CCT when different values of current were applied. The stress test showed that the prolongation of dye degradation can be improved using air gap and glass slid, with air gap being more effective. An optimum color rendering index (CRI) value of 61.2 is obtained. The white phosphor exhibited CIE values of 0.333, 0.3151 and color temperature (CCT) of 5405 K.