Title : A review of narrow band ultraviolet B light emissions in Gd3 activated phosphor host materials
Abstract:
In this review we have studied several research papers related to narrow-band (NB) ultraviolet light- B (UVB) emissions of Gd3+ doped phosphor materials in different host lattices. Ideal inorganic wide band host matrices such as phosphates, borates and fluorides are considered influential in narrow band UVB emission of Gd3+ doped ions. UVB emissions of the Gd3+ ion in the narrow band range of 310nm – 313 nm are due to 6P7/2 → 8PS7/2 transitions that falls within the action spectrum of phototherapy. Phototherapy makes use of artificial UVB radiation integrated in fluorescent lamps for treatment and cure of many skin diseases and disorders. However, due to the parity 4f-4f forbidden nature of Gd3+ transitions, Gd3+ excitation and emissions bands are relatively low, which makes them ineffective for therapeutic treatment of various skin disorders. To ameliorate this situation, various rare earth, or transition ions sensitizers such as Pr3+, Ce3+, Bi3+ are chosen, whose role is to absorb energy from the excitation source and transfer it to the Gd3+ activator ion, thereby enhancing the narrow UVB band emission for effective therapeutic treatments of skin diseases or disorders. In addition to this, phosphorescence narrow UVB emissions for skin treatment is also considered in the emerging field of medical science. Many factors pertaining to the choice of the various host phosphor materials for suitability in phototherapy are considered in this presentation.
