Browsing by Author "Yurdakul, Merve"

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Citation - WoS: 3
Citation - Scopus: 2
Dual- and Triple- Hetero-Atom Carbon Dots as Novel Additives for the Engineering of Defects Passivation To Boost Performance of Perovskite Solar Cells
(Springer, 2025) Kurukavak, Cisem Kirbiyik; Tok, Mutahire; Yurdakul, Merve; Kus, Mahmut
Methylammonium lead iodide (MAPbI3)-based perovskite solar cells (PSCs) offer highly efficient photovoltaics. However, several disadvantages such as poor stability and possibility of defect formation reducing film quality have restricted its commercialization. In this work, we reported the synthesis of dual- and triple-hetero-atom-doped carbon quantum dots (CQDs) via hydrothermal method and their effect of use as additive on the performance of PSCs. The boron (B) and phosphorous (P)-doped CQDs (B,P-CQDs), sulphur (S) and P-doped CQDs (S,P-CQDs), and B, S, and P-doped CQDs (B,S,P-CQDs) additives were described. Since these CQDs have many functional groups including hydroxyl (-OH), they can easily interact with Pb ions leading to the formation of PbO, as well as interaction with methyl ammonium ions. A reduced halide vacancy density and an increased nucleation energy of perovskite enhance crystal sizes and charge transfer. The passivation of surface defects reduces non-radiative recombination and ion migration, which plays an important role in photodegradation of the MAPbI3 films. Herein, the introduction of S,P-CQDs improved power conversion efficiency (PCE) from 10 to 15% and current density (Jsc) from 14.4 to 23.6 mA cm-2. PSCs added with dual- and triple-hetero-atom-doped CQDs showed narrower efficiency distribution in comparison to the control devices.
Citation - WoS: 3
Citation - Scopus: 2
Effect of Hetero-Atom Doping on the Structure and Optical Properties of Carbon Quantum Dots for the Sensitive Detection of Heavy Metal Ions
(Wiley, 2025) Kurukavak, Cisem Kirbiyik; Tok, Mutahire; Toprak, Aysegul; Yurdakul, Merve; Ersoz, Mustafa
Metal pollution in water sources due to modernization is a human health and environmental problem. Therefore, the highly fluorescent boron- and nitrogen-doped and nitrogen-doped carbon quantum dots (B,N-CQDs and N-CQDs, respectively) were synthesized and investigated to be used as a fluorescence sensor for metal ion detection. In this study, the synthesized B,N-CQDs and N-CQDs had an average size of 4-6 nm and 3-4 nm, respectively. The B,N-CQDs presented high sensitivity as 0.0090, 0.0086 and 0.0091 units per micromolar for Cr3+, Cu2+ and Fe2+, respectively, whereas the N-CQDs showed sensitivity as 0.0047, 0.0102, 0.0095 and 0.0121 units per micromolar for Cr3+, Cu2+, Fe2+ and Ni2+, respectively. In the concentration range of 10-80 mu M, the detection limits of B,N-CQDs and N-CQDs were found to be in the range of 13.9-65.5 mu g/L and 14.9-38.3 mu g/L, respectively. The result of the study clearly indicates that B,N-CQDs and N-CQDs can be seen as metal ion sensing devices with high sensitivity and low cost.
Perovskit Kuantum Noktaların Sentezi ve Karakterizasyonu
(2024) Tok, Mütahire; Kuş, Mahmut; Kırbıyık, Kurukavak Çisem; Yurdakul, Merve; Yılmaz, Tuğbahan
Bu çalışmada, Per-KN’lar (Perovskit Kuantum Nokta) LARP (ligand destekli yeniden çöktürme) yöntemi kullanılarak sentezlenmiştir. Bu yöntem ile perovskit kuantum noktaların sentezi; uygun miktarda PbX2 ve Cs2CO3’ın oleilamin, oktadesen ve oleik asit içinde bir süre karıştırıcı yardımıyla karıştırılarak dağıtılması daha sonra oda sıcaklığında ultrasonik çubuk yardımıyla 30 dk boyunca kuvvetli bir şekilde karıştırılmasıyla yapılmıştır. Per-KN’ lar 6500 rpm de 10 dakika boyunca santrifüjlenerek çözücüsünden ayrılmıştır. Per-KN’ ların optik analizleri UV–Vis ve fotolüminesans spektrometresi ile yapılmıştır. Per-KN’ ların yapısal karakterizasyonu için XRD tekniği kullanılmıştır. Sentezlenen Per-KN’ların optik bant aralığı enerjisi, halojenür bileşimi ayarlanarak neredeyse tüm görünür aralıkta (yaklaşık 400–700 nm) ayarlanabilmektedir. Per-KN’ların XRD desenlerinde kübik fazı doğrulayan standart veri dosyalarıyla tutarlı spesifik bölgelerde belirgin pikler görülmüştür. Sentezlenmiş olan Perovskit KN yapılarının kuantum verimleri CsPbCl3, CsPbBr3, CsPbI3 için sırasıyla %47,11; %53,48 ve %75,42 olarak hesaplanmıştır. Halojen içeriği değiştirildiğinde gözlenen renk değişiklikleri, floresan spektroskopisi ile ölçülmüş ve Per-KN’ ların PL spektrumlarının 14,2-22,7 nm bant genişlikleri ile tüm görünür spektral bölge üzerinde bant kenarı eksiton rekombinasyonuna atfedilebilecek olan ayarlanabilir emisyon bandı sergilediği görülmüştür.
Citation - WoS: 6
Citation - Scopus: 6
Separation of Pimelic Acid Using Tri-N in Various Organic Solvents by Reactive Extraction: Equilibrium and Modeling
(Amer Chemical Soc, 2022) Zeidan, Hani; Yurdakul, Merve; Martı, Mustafa Esen
Separation of carboxylic acids from dilute aqueous solutions is a challenging problem, and reactive extraction has been examined as an attractive alternative for this process. This study aims to investigate the reactive extraction of pimelic acid (PA) using tri-n-octylamine (TOA) in 1-hexanol, 1-octanol, xylene, and n-hexane. The highest extraction efficiency (E (%)) and distribution coefficient (K-D) were obtained at pH 3, which is the unadjusted pH of the aqueous PA solution. Extractive efficiency varied inversely with temperature and initial PA concentration but increased with the increase in TOA amount. The highest E (%) and K-D values (98.5% and 67.2, respectively) were obtained with 1-hexanol at initial TOA and PA concentrations of 0.2700 and 0.0375 mol/kg, respectively. The process was modeled using multilinear regression, and the model closely correlated with experimental results for all organic solvents tested.