2-Bromofenil boronik asit molekülünün spektroskopik ve geometrik özelliklerinin teorik ve deneysel olarak incelenmesi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu tezde 2 Bromofenil boronik asit (2Brpba) molekülünün deneysel ve teorik spektrumu incelendi. 2Brpba molekülünün infrared ve raman fuorier dönüşümleri kaydedildi. 2Brpba molekülünün yapısal ve spektroskopik analizleri Hatree-fock ve yoğunluk fonksiyon harmonik hesaplamalar ile yapıldı. 2Brpba molekülünün konformasyon analizi gerçekleştirildi ve kararlı konformasyonlar belirlendi. 2Brpba molekülünün kararlı konformasyonu DFT/B3LYP 6-311++G(d,p) ve HF 6-311++G(d,p) temel setleri kullanılarak belirlendi. 2Brpba molekülünün sadece bir formu en kararlı yapı olarak DFT/ B3LYP 6-31 G(d), DFT/ B3LYP 6-311++G(d,p) ve HF 6-311++G(d,p temel setleri kullanılarak belirlendi.Molekülün ölçeklendirilmiş infrared spektrum değerleri molekülün deneysel infrared spektrumu ile mukayese edildi. Gözlenen ve hesaplanan frekanslar arasında iyi bir uyum olduğu gözlendi. Son olarak 2Brpba molekülünün geometrik parametreleri infrared ve raman bandları şiddetleri molekülün deneysel sonuçları ile kıyaslanarak yorumlandı.In this thesis, the experimental and theoretical spectra of 2-Broophenylboronic acid (2Brpba) were investigated. The Fourier transform Raman and Fourier transform infrared spectra of 2Brpba molecules were recorded in the solid phase. The structural and spectroscopic analysis of 2Brpba molecules, has been carried out and stable conformation of 2Brpba were determined.The stable confermers of 2Brpba molecules, have been determined using DFT/B3LYP and HF level with the 6-311++ G(d,p) basis set. For the 2Brpba molecule, only one form was determined to be the most stable structure, by using DFT/B3LYP level with 6-31 G(d), 6-311++G(d,p) and HF 6-311++G(d,p) basis sets.The scaled values have been compared and interpreted with experimental FT-IR spectra of the molecule. Between the observed and calculated frequencies are found to be in good aggreement. Finally, geometric parameters of the 2Brpba molecule, infrared and raman bands and intensities were compare with result of experimental data of the 2Brpba molecule

Efficient Förster Resonance Energy Transfer Donors of In(Zn)P/ZnS Quantum Dots

We demonstrate a detailed investigation of the effect of the type and concentration of zinc precursor on the optical properties of In­(Zn)­P/ZnS quantum dots. We achieved up to 87% quantum yield along with 54 nm emission bandwidth for the green emitters with changing the concentration of the Zn precursors. Employing efficient green emitters as the donor species, we demonstrated an efficient Förster resonance energy transfer (FRET) couple of green and red emitting InP-based quantum dots. With a FRET efficiency level of 70.3% achieved (analyzed from the donor lifetime with and without an acceptor), we further demonstrated the enhancement of the acceptor emission nearly twofold due to the energy transfer. Our results provide new insights toward the understanding of the excitonic interactions among donor and acceptor quantum dots of the III–V family for light harvesting applications

Highly Efficient Cd-Free Alloyed Core/Shell Quantum Dots with Optimized Precursor Concentrations

The chemical composition, the emission spectral bandwidth, and photoluminescence quantum yield of a semiconductor quantum dot (QD) play an important role in the assessment of the performance of the applications related to the quantum dots. Quantum dots based on environmentally friendly compositions with high optical performance have been in demand for high-end technological applications. In this work, we propose and demonstrate a detailed synthesis approach for environmentally friendly and highly efficient InPZnS alloy/ZnS shell quantum dots. Following a systematic study of the ratio and type of the precursors involved, we achieved alloyed core–shell InPZnS/ZnS QDs with tunable emission across the visible spectrum, having a record quantum efficiency up to 78% along with a full width at half-maximum as narrow as 45 nm. The effect of the systematic shell growth has been further investigated using time-resolved photoluminescence characterizations along with the observation of the suppression of the nonradiative decay channels, with the photoluminescence lifetime prolonged from 20.3 to 50.4 ns. The development of highly efficient and environmentally friendly QDs will pave the way for robust, sustainable optoelectronic applications