High Emission Quantum Yield Tb³⁺‐Activated Organic‐Inorganic Hybrids for UV‐Down‐Shifting Green Light‐Emitting Diodes

Abstract

Solid-state light-emitting diodes (LEDs) are driving the lighting industry towards efficient and environmentally friendly lighting and displays. Current challenges encompass efficient and low-cost down-shifting phosphors with tuned emission colors. Green light lies on the low-loss optical transmission window in plastic optical fibers and plays a special role in the regulation of the human and plant circadian rhythms. Moreover, green-emitting phosphors may suppress the "green gap" found in semiconductor-based LEDs. In this work, a UV-photostable green-emitting complex, Tb(NaI) 3 (H 2 O) 2 , with NaI = nalidixic [a] Dr. complex to ≈ 0.82 in the hybrid. A green-emitting prototype was successfully fabricated by coating a commercial near-UV LED (365 nm) with the Tb 3+ -based organic-inorganic hybrids showing stable and pure-green light with Commission International de l'Eclairage (CIE) coordinates and an efficacy value of (0.33, 0.59), and 1.3 lm W -1 , respectively. Results and Discussion Structural CharacterizationThe detailed data relevant for the structural catherization is shown in Figures S1-S9. We will focus on the comparison between the FT-IR and Raman spectra of the pristine host, t-U(5000), and of the Tb 3+ -based hybrids, tU5Tb as shown in Figure 2. Similar information was obtained for the low-average molecular weight materials [t-U(3000) and tU3Tb], ( Figure S6).The medium-to-weak intensity FT-IR band at 927 cm -1 provides evidence that in tri-ureasils the polyoxyethylene chains attain complete disorder and the medium intensity peak at 1014 cm -1 is attributed to the strongly coupled vibrations of CH 2 rocking, and C-O and C-C stretching modes. The most Dr. Sandra F. H. Correia is a researcher in the Department of Physics at the University of Aveiro and CICECO -Aveiro Institute of materials. Nowadays, her scientific interests are mainly focused on organic-inorganic hybrids for applications in photovoltaics, namely, luminescent solar concentrators and down-shifting layers. Ricardo Fernandes received a MS Degree in Physics Engineering in 2016 at the University of Aveiro in Portugal. During his master's thesis he researched photo-luminescent complex materials coupled with organic-inorganic hybrids for UV down shifting. After graduation he received a research scholarship at Instituto de Telecomunicações to work in the area of optical communications with silicon based optical modulators. Dr. Lianshe Fu is a full-time researcher in the Department of Physics and CICECO-Aveiro Institute of Materials at University of Aveiro (Portugal) from 2007. Currently, his main research interests include lanthanide-based organic-inorganic hybrids for solid-state lighting such as white lightemitting diodes and carbon polymer dots for green photonics. Mariela M. Nolasco (b. Barquisimeto, VE) holds a Bachelor′s in EurJIC European Journal of Inorganic Chemistry 29 Si MAS NMR spectra were recorded with a Bruker III Avance 400 and Bruker III Avance 500 (9.4 T) spectrometer at 79.49 and 100.62 MHz, respectively. 29 Si MAS NMR spectra...

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