Ionic Liquid‐Assisted Route to Nanocrystalline Single‐Phase Phosphors for White Light‐Emitting Diodes

Abstract

White light-emitting diodes represent the future generation of domestic and public lighting, substituting the currently favored (compact) fluorescent lamps. Research on improving the performance and costs leads to a focus on processing constraints. The optimization of the grain size is judged to be an important tool for minimizing the necessary amount of (expensive rare-earth containing) phosphors. Using only one type of phosphor that emits white light instead of a mixture of three phosphors (one for blue, green, and red, respectively) will significantly improve the characteristics of future light-emitting diodes. Small, 6-8 nm-sized particles emit intense white light observable by the naked eye. The emission color has been studied by varying the dopant ion concentrations as well as the excitation wavelengths, yielding white light close to standard daylight.

Ionic liquids and deep eutectics as a transformative platform for the synthesis of nanomaterials

“…This synthetic concept can be easily transferred to (white light) emitting phosphors for light emitting diodes (LEDs), as seen in Fig. 12, 160,161 and even composite materials can be obtained for this purpose. 162 Phosphates can be made in a similar way to fluorides.…”

Particle Size and Crystal Phase Dependent Photoluminescence of La2Zr2O7:Eu3+ Nanoparticles

“…RE‐doped luminescent materials have widely been applying in various fields, such as lighting sources, display terminals, indicating devices, bioimaging, thermometry, and so on . Recently, crystal size and structure influence on the photoluminescence (PL) properties of luminescence materials are reported in many literatures which are ultimately affected by synthesis method, including synthetic procedure, processing environment and calcination temperature . Therefore, rational control over these synthetic factors for functional luminescence materials has become an important research topic in recent years.…”

“…[4][5][6] Recently, crystal size and structure influence on the photoluminescence (PL) properties of luminescence materials are reported in many literatures which are ultimately affected by synthesis method, including synthetic procedure, processing environment and calcination temperature. [7][8][9] Therefore, rational control over these synthetic factors for functional luminescence materials has become an important research topic in recent years. Controllable synthesis of them allows us to observe unique and interesting morphologies and explore growth mechanisms, moreover, to tune their chemical and physical properties based on our needs.…”

Synthesis of luminescent semiconductor nanoparticles in ionic liquids –the importance of the ionic liquid in the formation of quantum dots

“…All this gives the combination of ionic liquids with microwave irradiation good prospects for the synthesis of inorganic QDs. In the past, we have already beneficially used ILs as solvents, and sometimes even as smart reaction partners, in the microwave synthesis of photocatalysts, luminescent nanophosphors and nanosized thermoelectric materials (42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54).…”

“…We observed frequently, that the IL had a crucial influence on the particle size, morphology as well as, in case of polymorphic materials, the crystalline phase that formed for metal chalcogenides and halide particles synthesized by microwave heating in ionic liquids (42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52). Different ILs yielded under otherwise similar reaction conditions, different products.…”