New OLEDs Based on Zirconium Metal‐Organic Framework

Abstract

The search for new smart‐materials in solid‐state light‐emitting applications, like hybrid organic–inorganic light‐emitting devices (OLEDs), has seen an intense growth in the recent years. Among all the possibilities, metal‐organic frameworks (MOFs) have emerged as promising smart materials due to their chemical and structural properties. Herein, for the first time, the use of a Zr‐based MOF (Zr‐NDC, NDC = dimethyl 2,6‐naphthalenedicarboxylate) as electroluminescent active material in OLED devices is reported. The results indicate that, independently of the properties of the polymer used to form the emissive layer, the OLED emission is due to radiative electron and hole recombination in the MOF. A tuning of the optoelectronic properties of the device by incorporating Coumarin 153, (C153) and 4‐(Dicyanomethylene)‐2‐methyl‐6‐(4‐dimethylaminostyryl)‐4H‐pyran, into the MOF pores is demonstrated. Using different MOFLED architectures, and MOF composition, it is possible to elucidate the photoluminescence and electroluminescence mechanisms, providing the clues for further improvements. It is observed that the current density as well as the electroluminescent behavior depends on the dopant fluorophores. It is also shown that defects within the Zr‐MOF play a role in the OLED optoelectronic properties. The results clearly demonstrate the potential of MOFs as new tunable electroluminescent materials for OLED applications.

Electroactive Organic Building Blocks for the Chemical Design of Functional Porous Frameworks (MOFs and COFs) in Electronics

“…The virtually infinite possibilities for tuning the electronic and opticalp roperties of MOFs and COFs based on the appropriate selection, combination and modification of the organic building blocks, have prompted the interest in the implementation of such functionalporous frameworks in optoelectronics [28,30,146] and photonics. [24,147,148] The synthetic versatility of organic chemistry allows manipulating the electronic nature of different light-responsive organic buildingb locks, becoming an important strategy to fine-tune the performance of, for example, new MOF-and COF-based luminescents ensors, [24,149] photovoltaic [30] and electroluminescent devices, [150,151] with entire control over their physical properties. Herein, we focus on the recent advances on the design of functional porous frameworks based on light-responsive organic building blocks for optoelectronics andp hotonics applications.…”

Dual‐Guest Functionalized Zeolitic Imidazolate Framework‐8 for 3D Printing White Light‐Emitting Composites

“…The quantum yield (QY) values of the A+B@ZIF‐8 solid powder and the 3D printed composite pellet are 47.3% and 43.6%, respectively (Table S2, Supporting Information). In fact, their QY values are appreciably higher versus other solid‐state Guest@MOF luminescent materials found in the literature, for example: QY = 30% for Zr‐NDC MOF,30 QY = 17.4% for ZJU‐28,28 and QY = 20.4% for iridium‐complex@MOF 17…”

“…There is an increasing number of studies on Guest@MOF research reporting the encapsulation of a wide range of functional guests, such as rare‐earth metals, organic dyes, carbon dots, quantum dots, and metal complexes to achieve tuneable luminescent properties and white light generation 17–19,25–32. Indeed, the majority of current efforts are much dependent on the use of non‐economical and non‐environmentally friendly rare‐earth metals, see the statistics in Figure S1, Supporting Information.…”

Femto- to Millisecond Time-Resolved Photodynamics of a Double-Functionalized Push–Pull Organic Linker: Potential Candidate for Optoelectronically Active MOFs

“…The large value obtained for ∆μ (10.69 D) reflects a strong CT character of the excited molecule. This large charge migration may open interesting photochemistry in the related MOF based on this linker, similar to a photoinduced ligand-metal charge transfer (LMCT) or metal-ligand charge transfer (MLCT) reaction [16,20,21,39]. The fluorescence quantum yields (Φ) of Me2CANADC in the different solvents were also measured by using an integrated sphere, and the obtained values are reported in Table 1.…”

“…In fact, MOFs and guest@MOF composites have emerged as versatile candidates in energy management [6,7], storage of fuels such as H 2 and methane [8,9], and biological or medical applications [10][11][12]. Among all the possible MOF structures and composites, those who emit light have become very popular because of their possible integration in different photonic technologies as luminescent chemical and physical sensors or optoelectronic devices [13][14][15][16]. The luminescence properties of MOFs may arise from the organic linker, the metal clusters, or through internal interactions, such as ligand-to-metal, metal-to-ligand, ligand-to-ligand or metal-to-metal charge transfer interactions [17][18][19][20][21].…”