Investigation of nanomaterial supported fluorophore, phosphor or phosphor-blends in polymeric matrices for optoelectronic applications

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Dokuz Eylül Üniversitesi, Fen Fakültesi, Yeni Bölümler (Rezerv), Türkiye

Tezin Onay Tarihi: 2022

Tezin Dili: İngilizce

Öğrenci: UTKU ULUCAN

Danışman: Kadriye Ertekin

Özet:

INVESTIGATION OF NANOMATERIAL SUPPORTED FLUOROPHORE, PHOSPHOR OR PHOSPHOR-BLENDS IN POLYMERIC MATRICES FOR OPTOELECTRONIC APPLICATIONS

ABSTRACT

 

In this thesis we investigated the interactions between the commercially available LED phosphorus and nano-scale materials or dyes in terms of their emission abilities in polymers. In the first part of the thesis, photoluminescence of the Eu²⁺ doped Ca-α-Sialon (Ca-α-SiAlON:Eu²⁺), Ce³⁺ doped lutetium aluminum garnet (LuAG:Ce³⁺) and their binary blends with the quinine sulphate (QS) were investigated by steady-state and decay time measurements. The Ca-α-SiAlON:Eu²⁺ exhibited 44% increase in the intensity when blended with the QS. Similarly, the binary blend of QS-LuAG:Ce³⁺ exhibited 98%  enhancement in the intensity. Excited state lifetimes of the phosphors were also studied in nanosecond and microsecond time scales, respectively. Spectral data presented some evidence for the donor-acceptor relationship of the QS/ Ca-α-SiAlON:Eu²⁺ and QS/LuAG:Ce³⁺ counterparts where the QS was the donor. The offered phosphor blends, exhibited enhancement in the optical brightness without any spectral shift.

 

In the second part of the thesis, CO₂ sensitive HPTS dye was used along with the bioactive glasses and ionic liquid. The bioactive glasses equipped with the rare earths of Er³⁺, Tb³⁺ and Er³⁺and Tb³⁺, were chosen due to their porous structure, optical transparency and intrinsic fluorescence. After spectral characterization steps we exposed the composites towards varying concentrations of the CO₂ and recorded the intensity based response both in steady-state and kinetic mode. We also determined the decay times in the absence and presence of the CO₂. We obtained promising results from the studies performed by using the bio-compatible bioactive glasses in terms of enhanced optical brightness and CO₂ sensitivity.

 

Keywords: Fluorescence, bioactive glass, HPTS, carbon dioxide.