Luminophoren

Luminophoren, a term commonly used in German, refers to a substance or material that emits light after absorbing energy. The emitted light is a form of luminescence that persists after excitation and is not due to heat. Luminophoren are central to many lighting, display, and sensing technologies and are distinguished from incandescence.

Luminophores span several classes, including organic luminophores (fluorophores in dyes and polymers), inorganic phosphors (ceramics and crystals), semiconductor quantum dots, and lanthanide-doped materials such as upconversion particles. The common feature is a system of energy states that emits light when returning to lower energy levels, with emission color determined by the energy gap and material structure.

Different mechanisms produce luminescence: fluorescence (fast decay, typically nanoseconds), phosphorescence (longer decay), chemiluminescence and electrochemiluminescence (emission from chemical reactions or electrochemical processes). Energy transfer processes, such as Förster resonance energy transfer, can alter emission characteristics or enable multiplexing in complex systems.

Key properties include emission spectrum and color, quantum yield (the efficiency of photon emission), excited-state lifetime, and photostability. In practical applications, luminophores are selected for compatibility with matrices, solvents, and, in biological contexts, for biocompatibility and ease of functionalization.

Applications cover displays (organic light-emitting diodes), solid-state lighting, bioimaging and biosensing, fluorescence-based assays, security inks, and optical data storage. The choice of luminophore balances brightness, stability, spectral suitability, and safety.

Representative examples include organic dyes such as fluorescein and rhodamine; inorganic phosphors such as strontium aluminate doped with europium and dysprosium; semiconductor quantum dots like CdSe/ZnS; and upconversion materials such as NaYF4:Yb,Er.