Person: YAVUZ, İLHAN
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Publication Metadata only Oscillatory behavior of interlayer Dzyaloshinskii-Moriya interaction by spacer thickness variation(2024-04-01) YAVUZ, İLHAN; DEĞER, CANER; Demiroglu E., Hancioglu K., YAVUZ İ., Avci C., DEĞER C.The interlayer Dzyaloshinskii-Moriya interaction (IL-DMI) has recently emerged as an ingredient promoting chiral orthogonal coupling between adjacent magnetic layers in multilayered systems. IL-DMI offers an additional tuning knob to engineer the magnetic behavior in spintronic devices, which could be useful for nonvolatile logic and memory technologies. Here, we systematically study, via first-principles calculations and the three-site Fert-Lévy model, the spacer thickness dependence of the IL-DMI between an out-of-plane ferrimagnet TbCo and an in-plane ferromagnet Co through Pt, Ir, Pd, and Ru. We observed a damped oscillatory behavior with increasing spacer thickness in all cases with characteristic amplitude and periodicity. Furthermore, we established a direct correlation between the IL-DMI and density of states of bottom and top Co atoms, dominated by the spacer thickness, which is attributed to a hybridization of electronic orbitals. Based on this compelling evidence, we propose that the electronic orbital hybridization contributes to the microscopic origin of the IL-DMI metallic magnetic multilayers. We anticipate that our results will provide insights into the understanding and precise control of IL-DMI in a wide range of materials and spintronic device concepts.Publication Open Access Chelation strategy induced blue-shift for efficient deep-blue perovskite light-emitting diodes(2024-01-01) YAVUZ, İLHAN; Xia Y., Zhang Z., Zhou Y., Li Y., Wang B., Wang K., Chen C., Chen J., YAVUZ İ., Xing G., et al.Metal halide perovskite, regarded as a potential material for next-generation display and lighting applications, has attracted great attention [1,2]. The development of blue perovskite lightemitting diodes (PeLEDs) remains stagnant compared with their green and red counterparts in recent years [3–8]. Meanwhile, among the emitters of different blue emission regions, the development of deep-blue PeLEDs urgently required by the display application lagged significantly behind. Therefore, conducting research on deep-blue PeLEDs (<460 nm) to achieve the desired color gamut in the range of the Commission Internationale de I’Eclairage (CIE) color coordinates approaching (0.131, 0.046) that fulfill the Rec. 2020 specification holds paramount importance. However, obtaining deep-blue emission in perovskites through the straightforward implementation of the common strategies involving excessive chloride incorporation and dimensional reduction presents a significant challenge.Publication Metadata only Mitigating Buried-Interface Energy Losses through Multifunctional Ligands in n-i-p Perovskite/Silicon Tandem Solar Cells(2024-01-01) DEĞER, CANER; YAVUZ, İLHAN; Zhang S., Wang J., Kalasariya N., Dally P., DEĞER C., YAVUZ İ., Razzaq A., Vishal B., Prasetio A., Utomo D. S., et al.Fabricating efficient monolithic n-i-p perovskite/silicon tandem solar cells remains challenging, as evidenced by substantial recombination losses at the buried interface between the NbOx electron transport layer (ETL) and perovskite. Herein, we introduce a self-assembled fullerene (C60-SAM) interlayer at this interface, with a large monovalent organic cation incorporated. We find this enhances the surface conductivity of the ETL, mitigates interface recombination, and reduces the energetic mismatch with the overlying perovskite. At the device level, this results in efficient electron extraction and suppressed device hysteresis, substantiated by drift-diffusion simulations. The combination of these improvements led to hysteresis-free n-i-p perovskite/silicon tandem solar cells on textured silicon with an efficiency of 27% (over 1 cm2) and an open-circuit voltage reaching 1.9 V.