Browsing by Author "Korkmaz, U"

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    Adaptation and the Psychometric Properties of Turkish version of the Structured Clinical Interview for the DSM-5-Personality Disorders - Clinician Version (SCID-5-PD/CV)
    Bayad, S; Alp-Topba, Ö; Kocabas, T; Elbir, M; Gökten-Ulusoy, D; Korkmaz, U; Araz, O; Ergüner-Aral, A; Karabekiroglu, A; Aydemir, Ö
    Objective: The aim of this study is to demonstrate the validity and reliability of the Categorical and Dimensional Psychometric Properties of the Structured Clinical Interview for DSM-5 Personality Disorders (SCID-5-PD) after its translation to the Turkish. Method: The study was carried out with 102 volunteers from two university hospitals. The SCID interview was conducted by two experienced psychiatrists who interchanged positions as interviewer and observer; and completed the research forms without discussing the patient. The diagnostic agreement between the interviewers and the Kappa coefficient were calculated. Divergent and convergent validity analyses were carried out for diagnostic validity and the scores obtained from the self-report form as well as the dimensional evaluation scores were used in the statistical analyses. Results: The group mean age for volunteers was 39.6 +/- 11.6 years and 66.7% consisted of females. The Kappa values for personality categories were 0.79 for avoidant personality structure, 0.64 for dependent personality structure, 0.81 for obsessive-compulsive personality structure, 0.76 for paranoid personality structure, 0.49 for schizotypal personality structure, 0.90 for histrionic personality structure, 0.66 for narcissistic personality structure, 0.89 for borderline personality structure and 0.71 for antisocial personality structure. Dimensional evaluation showed significant correlation with the diagnostic agreement between the interviewers and also with the scores of the self-report forms completed by the participants. Conclusion: The results demosntrated that the Turkish version of the Structured Clinical Interview for DSM-5 Personality Disorders (SCID-5-PD-CV-TR) is valid and reliable.
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    The coupling of blue emitting carbon dots with Eu3+/Tb3+ co-doped luminescent glasses for utilization in white light emitting diodes
    Korkmaz, U; Özlem, B; Erol, E; Alas, MÖ; Altürk, RG; Ersundu, MÇ; Ersundu, AE
    Lanthanide-doped luminescent glasses have attracted tremendous attention in modern optoelectronic applications, especially for solid-state white light-emitting diodes (WLEDs). Eu3+/Tb3+ co-doped luminescent glasses are well-known to emit intense yellowish-orange light resulting from the energy transfer from green-emitting sensitizer Tb3+ ions to red-emitting activator Eu3+ ions. Obtaining highly efficient blue light from lanthanide ions remains a challenge due to their weak down-converted emission. In this work, we attempt to use the unique characteristics of blue-emitting carbon dots (BCDs), i.e., a broad emission spectrum, ease of synthesis, and high stability, to compensate for this blue light deficiency problem. Correspondingly, a new strategy is proposed by coupling BCDs with Eu3+/Tb3+ co-doped glasses for their potential utilization in WLEDs. Hence, Eu3+/Tb3+ co-doped glasses are prepared in different thicknesses, i.e., 0.8, 1, and 1.5 mm, via the conventional melt-quenching method and subsequently spin-coated with BCDs to achieve adjustable photoluminescence quantum yield (PLQY) values. Ultimately, a proof-of-concept WLED is prepared using a 0.8 mm thick BCD-coated Eu3+/Tb3+ co-doped luminescent glass exhibiting outstanding luminescence performance with a CRI value of 92, a CCT of 4683 K, color coordinates of (x = 0.3299, y = 0.3421), a satisfying PLQY value of 55.58%, and a corresponding LER value of 316 lm W-1 under the excitation of a 375 nm UV LED. BCD-coated Eu3+/Tb3+ co-doped luminescent glasses show excellent stability against photobleaching, temperature variations, and humidity. The findings of this work indicate that the coupling of BCDs with Eu3+/Tb3+ co-doped luminescent glasses holds great potential as a substitute for traditional solid-state lighting sources.
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    Bright white light emission from blue emitting carbon dot-coated Dy3+- doped luminescent glasses
    Özlem, B; Korkmaz, U; Erol, E; Alai, MÖ; Meray, Z; Altürk, RG; Ersundu, MC; Ersundu, AE
    Dy3+-doped luminescent glasses have received great attention due to their ability to emit white light at a suitable yellow-to-blue intensity ratio. However, achieving bright white light using single Dy3+-doped glasses remains a challenge due to the hypersensitivity of the emission band at 575 nm - usually resulting in intense yellow emission. In this work, we present a novel approach for compensating for the blue emission deficiency of Dy3+ to produce resin-free white light-emitting diodes (WLEDs) by synthesizing two series of Dy3+-doped glasses from tellurite and silicate systems on which blue-emitting carbon dots (BCDs) are spin-coated. The structural, chemical, optical, and luminescence properties of tellurite and silicate glasses are compared and discussed in detail. White light emissions are obtained upon 365-nm excitation for BCD-coated Dy3+-doped tellurite and silicate glasses with color coordinates of (x = 0.31, y = 0.33) and (x = 0.31, y = 0.34) and correlated color temperatures (CCT) of 5518 K and 5316 K, respectively. BCDs coating increases photoluminescence quantum yield (PLQY) values from 3.10 % to 5.62 % and from 20.81 % to 31.49 % for tellurite and silicate glasses, respectively. Ultimately, the findings in this work show the potential of BCD-coated luminescent glasses with excellent luminescent properties to be considered in solid-state lighting applications. (c) 2022 Elsevier B.V. All rights reserved.