Blue-Light-Emitting Photostable Hybrid Films for High-Efficiency Large-Area Light Converter and Photonic Applications

Abstract

A blue fluorophore of Schiff base zinc complex is prepared by a hydrolysisfree solution-based synthetic method. Under ultraviolet (UV) excitation, the complex produces blue emission with a quantum yield (Q) of 42.6% in methylene chloride and 24.0% in standalone powder form. Quantum mechanical calculations show that the blue emission is generated by the change in the chemical state of the ligand associated with the complexation with Zn cations. Thin films of Zn complexes incorporated in polymethylmethacrylate (PMMA) and cellulose acetate butyrate (CAB) polymers are also prepared by dispersing the complexes into the polymer matrices. These hybrid polymer films exhibit several notable features, particularly enhanced luminescence efficiency (with maximum Q of 85.8% for PMMA and 30.0% for CAB) and scalability for fabrication over a large area while retaining the original properties of the host polymers. Light-emitting diodes are also fabricated using the CAB hybrid thin films, and they show a Q of 43.2% with excellent photostability. The complex and its hybrid films demonstrate their great potential for such applications as UV-to-blue conversion devices in photoelectronics, solar-cell concentrators, solid-state lighting and display, and greenhouse agriculture.

Long-living and highly efficient bio-hybrid light-emitting diodes with zero-thermal-quenching biophosphors

“…As the most remarkable result, long-living (>150 days) and highly efficient (~130 lm/W) Bio-HLEDs were realized. This strongly contrasts with the prior-art in Bio-HLEDs based on FPs-i.e., average <300 h and <50 lm/W [27][28][29][30][31][32][33][34] , those based on bio-matrices-i.e., average <200 h and <10 lm/ W 15,[22][23][24][25][26] , other HLEDs based on small molecules-i.e., <1000 h and <150 lm/W [16][17][18] and iridium(III) complexes-i.e., <1000 h and <100 lm/W 38,39 . Hence, this work opens a way to stabilize FPs in common polymer matrices for optics, providing a significant advance in the emerging Bio-HLED concept.…”

“…These concerns have fueled the renaissance of hybrid LEDs (HLEDs) [13][14][15] . In these devices, the IPs are replaced by organic phosphors (OPs) ranging from polymer matrices doped with artificial emitters [16][17][18] , over luminescent metal organic frameworks (MOFs) [19][20][21] , to biophosphors based on either DNA/protein matrices to host artificial emitters 15,[22][23][24][25][26] or fluorescent proteins (FPs) embedded in polymer/MOF matrices or alone 15,[27][28][29][30][31][32][33][34] . Like IPs, OPs must exhibit a narrow emission with high photoluminescence quantum yields (ϕ), high molar extinction coefficients (ε), outstanding photobleaching stabilities under operating conditions, and low heat generation and thermal quenching upon continuous excitation.…”

Schiff Bases and Their Complexes in Organic Light Emitting Diode Application

“…Yet another Schiff base-Zn complex 4 which emitted blue light was synthesized by Kang et al through a hydrolysisfree solution-based method. 69 (Fig. 4b) Thin films were prepared by dispersing the metal-organic complex 4 in polymethylmethacrylate (PMMA) and cellulose acetate butyrate (CAB) polymer matrices.…”

In situ wrapping carbon dots towards robust, durable and transparent tri-layer films with precise spectral conversion and excellent self-cleaning properties

“…Light conversion film (LCF), a type of functional film that allows for optical wavelength conversion, is crucial in improving solar energy utilization, particularly in the fields of photovoltaic power 1 and greenhouse agriculture. 2,3 For example, carotene, chlorophylls a and b as well as other photosynthetic pigments strongly absorb visible light in the blue (400–500 nm) and red (630–700 nm) regions.…”