CaAl2O4: Dy+3 ve CaAl2O4: Sm+3 Işıldar Tozlarının Üretimi ve Karakterizasyonu

Öz

Kalsiyum alüminat, CaAl2O4, inorganik fosforlarda oldukça işlevsel ve iyi bilinen bir konut malzemedir. Bu konut yapıdaki fosforlar çoğunlukla Eu2+ ile katkılanmakla birlikte farklı tipte nadir toprak iyonları da çalışılmıştır. Bu çalışmada CaAl2O4 tipindeki konut yapı, Dy3+ ve Sm3+ ile farklı konsantrasyonlarda katkılanmıştır. Ca1-xAl2O4: Dy+3x (x= 0.008, 0.012, 0.02, 0.03) ve Ca1-yAl2O4: Sm+3y (y= 0.008, 0.012, 0.02, 0.03) fosforları toz numuneler halinde katı-hal tepkimesi yöntemiyle sentezlenmişlerdir. Isıl işlemlerden sonra XRD analizi yapılarak nadir toprak iyonları katkılı fosfor tozları monoklinik CaAl2O4 yapısında indislenmiştir. Fotolüminesans özellikler katkı iyonuna bağlı olarak belirlenmiştir. Dy+3 katkılı fosforlara ait 484 nm ve 577 nm iki belirgin pik, 4F9/2 → 6H15/2 ve 4F9/2 → 6H13/2: Dy+3 geçişlerine aittir. Sm3+ katkılı fosforlarda ise 565 nm, 604 nm, 649 nm, and 712 nm’deki pikler 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2, 4G5/2 → 6H11/2: Sm+3 geçişleri ile ilgilidir. Commission International De IEclairage (CIE) 1976 renklilik diyagramından faydalanılarak fosfor tozlarına ait ışıma dalga boylarına bağlı olarak belirlenen (uꞌ = 0.21805, vꞌ = 0.52537) ve (uꞌ = 0.36078, vꞌ = 0.54567) koordinatlarına göre sırasıyla Dy+3 iyonları sarı-turuncu bölgede, Sm+3 iyonları ise kiremit kırmızısı renk bölgelerinde ışımaların oluştuğunu göstermiştir. Sonuç olarak iki farklı alternatif nadir toprak iyonu ile katkılanan CaAl2O4 fosforlarının LED’lerde ve görüntü oluşturma uygulamalarında değerlendirilmeleri mümkündür.

Anahtar Kelimeler

• CaAl2O4
• Dy+3
• Sm+3
• katı hal tepkimesi yöntemi
• LED fosforları

Synthesis and Characterization of CaAl2O4: Dy3+ and CaAl2O4: Sm3+ Phosphor Powders

Öz

Calcium aluminate, CaAl2O4 is efficient and well known host material for inorganic phosphors. Although this host structure is mostly doped with Eu2+, different types of rare earth ions have also been studied. In this study, attention was drawn to CaAl2O4 type phosphors doped with Dy3+ and Sm3+ at different concentrations. Ca1-xAl2O4: Dy3+x (x= 0.008, 0.012, 0.02, 0.03) and Ca1-yAl2O4: Sm3+y (y= 0.008, 0.012, 0.02, 0.03) phosphors were synthesized as powder samples through the solid-state reaction method. After heat treatments, monoclinic CaAl2O4 structure was confirmed for all rare earth doped samples by the XRD analysis. PL characteristics of samples depend on activator ion. The PL emission spectra of Dy3+ doped powder samples show two strong bands at 484 nm and 577 nm which are attributed to a typical 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ions. Sm3+ activated phosphors have the emission peaks at 565 nm, 604 nm, 649 nm, and 712 nm which are assigned to Sm3+ transitions: 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2, 4G5/2 → 6H11/2, respectively. The Commission International De IEclairage (CIE) 1976 chromaticity coordinates were evaluated from the emission spectra in two different rare earth ion doped phosphors, the values (uꞌ = 0.21805, vꞌ = 0.52537) and (uꞌ = 0.36078, vꞌ = 0.54567) were colors of yellow-orange and brick red, respectively. Consequently, synthesized Ca1-xAl2O4: Dy3+x (x= 0.008) and Ca1-xAl2O4: Sm3+y (y= 0.008) phosphors emitting in different color regions can be useful for LED’s and display applications.

Anahtar Kelimeler

• CaAl2O4
• Dy3+
• Sm3+
• solid state reaction method
• LED phosphors

Kaynakça

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