White light emission in metal-organic frameworks (MOFs)
Creators: name: Zheng, Min
Publisher: name: figshare
Year: 2022
Subjects: subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Crystallography
subject: Inorganic Chemistry
subject: 30299 Inorganic Chemistry not elsewhere classified
subject: 30202 f-Block Chemistry
subject: 30207 Transition Metal Chemistry
subject: 30307 Theory and Design of Materials
subject: 30306 Synthesis of Materials
subject: 30304 Physical Chemistry of Materials

description: <b>Introduction</b> The increasing global consumption of energy has led to the advancement and utilization of smart devices that save energy and nonlinear optical materials that are energy efficient for use in state-of-the-art applications. Solid-state white-light emitting materials have remarkable properties like energy-saving and a long operational lifespan, which has resulted in their widespread use for large-screen displays, as well as diffuse broadband light emission. First, nonlinear optical functional materials are subdivided according to the material they are constructed inorganic phosphors, or organic molecules semiconductors. In a different way, optical functional materials that are emissive can be classified into two types according to the method by which they are stimulated to release light, namely, through ultraviolet excitation or electrical excitation. These optically functional nonlinear materials are more inefficient than traditional incandescent lamps or eco-friendly compared to mercury and fluorescent lamps. <b>How to introduce white light emission property into MOF?</b> In general there are two ways to get optical emission of white light in metal-organic frameworks (MOFs): primary one is the use of dichromatic emitters: blue and yellow, or red and blue or alternatively, by employing trichromatic emitters that blend all three of the primary colors (red green, blue as well as blue). White light is produced through the use of different dopants or phase matrices, such as organic compound, metal complexes, nanomaterials such as hybrid organic-inorganic materials and inorganic phosphors. These types of materials have distinct features that allow them to benefit for generating white light however, often it is necessary to mix various types of materials in order to achieve the desired result. However optical emission that is nonlinear from single species can also be accomplished and spans the entire visible spectrum. The benefit of these devices is the fact that they comprise only of one, precisely defined emitter. This makes the creation of materials that are lighter and less bulky and at the same time are highly suitable to the development for optical components. Materials and devices that emit white light are versatile and attractive for their particular applications like optical functional materials in emitting panels with full-color, as well as backlights. The materials that are white-emitting are metal complexes, doped metals or hybrid inorganic materials as well as small organic molecules quantum dots, nanocrystals, as well as polymers. With well-defined and well packed pore structures, superior stability, and promising linear and nonlinear optical properties luminescent MOFs are attracting more interest due to their potential to emit white light. To date there is a tiny fraction of MOFs have been found to exhibit white-light emission. The majority of efforts in generating white light emission focused on doping and encapsulation of the lanthanide Ions according to three primary colors. Thus, the lanthanide-ion ions have recently become the focus of light-emitting white MOFs including the distinct green-light emission, of terbium and the red-light emission europium are frequently used to create the three primary colors. They also have a blue emission ligand. The linkers with strong blue-light emission are usually chosen for blue emission most of their blue-light emission was utilized without any adjustment. In reality the emission of an application ligand is optimized by altering the excitation wavelength so that it can produce the necessary emission. This can, in turn, be matched to the system emission for white-light emission across the entire MOFs. Of course, is dependent on a ligand having a adequate emission, and sufficiently strong to allow for the diminution of emission intensity at the optimal excitation wavelength. The same is true for the MOF:the metal nodes in the MOF can be assigned to metals that have minimal or no impact upon their light emission of ligands and to reduce the complexity of signal modulation. <b>Key takeaways</b> Researchers have always been keen to find a feasible way to create and improve MOFs to control their optical properties, including white-light emission. Based on the current state of affairs it is appropriate to select the ligand with the needed emission within itself to create monochromatic MOFs that then encapsulate the correct lanthanide to control white-light emission. Ion exchange is a suitable method to introduce lanthanide as it was previously used to control the light emission of transition MOFs and particularly lanthanide metal-organic frameworks (LMOFs). It is, however, sensible to control on molecular level the coordination between the lanthanide ion and ligand since this could result in a strong energetic transfer within the metal-organic structures and affect the modulation of white-light emission more complex.