Advanced Performance Photoluminescent Organic Light-Emitting Diodes Enabled by a Natural Dye Emitters Considering a Circular Economy Strategy

Organic optoelectronic devices receive appreciable attention due to their low cost, ecology, mechanical flexibility, band-gap engineering, lightness, and solution process ability over a broad area. Here, we designed and studied an organic light-emitting diodes (OLEDs) consisting of assembly of natural dyes extracted from of noble fir leaves (evergreen) and blue hydrangea flowers and mixed with poly-methyl methacrylate (PMMA) as a light emitters. We experimentally demonstrate effective red and green photoluminescence due to the excitation natural dye-PMMA nanostructures by laser/ photodiode blue light. The UV-Visible absorption and photoluminescence spectroscopy, ellipsomentric and Fourier transforms infrared methods together with optical microscopy were achieved for confirming and characterizing the properties of light-emitting diodes based on natural dyes. We highlighted the optical and physical properties of two different natural dyes, and demonstrated how such characteristics can be exploited to make efficient LED devices. A strong pure red emission with narrow full-width at half maxima (FWHM) of 23 nm in the noble fir dye-PMMA layer and a green emission with FWHM of 45 nm in blue hydrangea dye-PMMA layer have been observed. It was revealed that adding the MoS2 monolayer to the nanostructure can significantly enhance the photoluminescence of natural dye due to strong correlation between emission bands of the inorganic-organic emitters and back mirror reflection of the excitation blue light from monolayer. Based on investigation of two natural dyes we demonstrated viable pathways for scalable manufacturing of the efficient OLEDs consisting of assembly of natural dyes -polymer through low-cost, pure ecological and human convenient processes.