Preparation And Luminescence Properties Of Mn(?) Doped Fluoride Red Phosphors For White LED Application

White LED technology has become a new generation of environmentally friendly energy-saving lighting source technology with its small size,high luminous efficiency,fast response time,long use time,energy saving and environmental protection.Phosphor is the key material for white LED to achieve fluorescence conversion.At present,commercial white LED technology is based on In Ga N chips to excite yellow phosphors to produce white light,but the lack of red components leads to a high color temperature and low color rendering index for this white light.In this thesis,in response to the demand for high-efficiency red light components of high color rendering white LEDs,a simple co-precipitation method was used to synthesize Mn⁴⁺ ion-activated fluoride red phosphors,and the structure and luminous properties were analyzed and studied.The main research contents are as follows:?1?A series of K₂MnF₆/KHF₂ red phosphors were prepared by a simple one-step method,and their morphology and photoluminescence?PL?properties were studied.The prepared phosphor shows strong red emission under the excitation of 454 nm blue light,and has the strongest emission peak at 631 nm.At the same time,the HF concentration and the mass ratio between KHF₂ and KMn O4 are different for the prepared K₂MnF₆/KHF₂.The luminescent properties of phosphors have a great effect;in addition,the PL intensity and thermal stability properties and the quantum yield of the phosphors excited under blue light have been studied and compared with relatively commercially used phosphors.Finally,by using a 450 nm blue chip with YAG: Ce³⁺ and the prepared K₂MnF₆/KHF₂ phosphor,a bright LED with high color rendering performance of Ra = 86.8 was fabricated.The results show that K₂MnF₆/ KHF₂ phosphors can promote their potential applications in indoor lighting and backlighting.?2?K₂SiF₆: Mn⁴⁺ red phosphor was prepared by co-precipitation method without HF green,and the phase structure of the phosphor of the system was analyzed by XRD.The effects of different acids on phosphor synthesis and luminous intensity were studied.The research determined that H3PO4 was used instead of HF for phosphor preparation,and the optimal concentration of H3PO4 was found to achieve K2 Si F6:Mn⁴⁺ red phosphor intensity enhancement.Using PLE/PL and its quantum efficiency accessory,analysis technology is used to discuss and study its spectral characteristics,fluorescence thermal stability,and fluorescence quantum yield.Finally,the red fluorescent powder prepared in this paper was packaged into a white LED with YAG: Ce³⁺ and 450 nm blue chips,and the improvement of the color rendering index of white LED was studied by the introduction of red fluorescent powder.