Browsing by Author "Isik, Furkan"

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Open Access
High external quantum efficiency light-emitting diodes enabled by advanced heterostructures of type-ii nanoplatelets
(American Chemical Society, 2023-03-13) Durmusoglu, Emek G.; Hu, Sujuan; Hernandez-Martinez, Pedro Ludwig; Izmir, Merve; Shabani,Farzan; Guo, Min; Gao, Huayu; Isik, Furkan; Delikanli, Savas; Sharma, Vijay Kumar; Liu, Baiquan; Demir, Hilmi Volkan
Colloidal quantum wells (CQWs), also known as nanoplatelets (NPLs), are exciting material systems for numerous photonic applications, including lasers and light-emitting diodes (LEDs). Although many successful type-I NPL-LEDs with high device performance have been demonstrated, type-II NPLs are not fully exploited for LED applications, even with alloyed type-II NPLs with enhanced optical properties. Here, we present the development of CdSe/CdTe/CdSe core/crown/crown (multi-crowned) type-II NPLs and systematic investigation of their optical properties, including their comparison with the traditional core/crown counterparts. Unlike traditional type-II NPLs such as CdSe/CdTe, CdTe/CdSe, and CdSe/CdSexTe1–x core/crown heterostructures, here the proposed advanced heterostructure reaps the benefits of having two type-II transition channels, resulting in a high quantum yield (QY) of 83% and a long fluorescence lifetime of 73.3 ns. These type-II transitions were confirmed experimentally by optical measurements and theoretically using electron and hole wave function modeling. Computational study shows that the multi-crowned NPLs provide a better-distributed hole wave function along the CdTe crown, while the electron wave function is delocalized in the CdSe core and CdSe crown layers. As a proof-of-concept demonstration, NPL-LEDs based on these multi-crowned NPLs were designed and fabricated with a record high external quantum efficiency (EQE) of 7.83% among type-II NPL-LEDs. These findings are expected to induce advanced designs of NPL heterostructures to reach a fascinating level of performance, especially in LEDs and lasers.
Open Access
Polariton lasing in Mie-resonant perovskite nanocavity
(Editorial Office of Opto-Electronic Advances, 2024-01-19) Masharin, Mikhail A.; Khmelevskaia, Daria; Kondratiev, Valeriy I.; Markina, Daria I.; Utyushev, Anton D.; Dolgintsev, Dmitriy M.; Dmitriev, Alexey D.; Shahnazaryan, Vanik A.; Pushkarev, Anatoly P.; Isik, Furkan; Iorsh, Ivan V.; Shelykh, Ivan A.; Demir, Hilmi V.; Samusev, Anton K.; Makarov, Sergey V.
Deeply subwavelength lasers (or nanolasers) are highly demanded for compact on -chip bioimaging and sensing at the nanoscale. One of the main obstacles for the development of single -particle nanolasers with all three dimensions shorter than the emitting wavelength in the visible range is the high lasing thresholds and the resulting overheating. Here we exploit exciton-polariton condensation and mirror -image Mie modes in a cuboid CsPbBr 3 nanoparticle to achieve coherent emission at the visible wavelength of around 0.53 mu m from its ultra -small ( approximate to 0.007 mu m 3 or approximate to lambda 3 / 2 0) semiconductor nanocavity. The polaritonic nature of the emission from the nanocavity localized in all three dimensions is proven by direct comparison with corresponding one-dimensional and two-dimensional waveguiding systems with similar material parameters. Such a deeply subwavelength nanolaser is enabled not only by the high values for exciton binding energy ( approximate to 35 meV), refractive index (>2.5 at low temperature), and luminescence quantum yield of CsPbBr 3 , but also by the optimization of polaritons condensation on the Mie resonances with quality factors improved by the metallic substrate. Moreover, the key parameters for optimal lasing conditions are intermode free spectral range and phonons spectrum in CsPbBr 3 , which govern polaritons condensation path. Such chemically synthesized colloidal CsPbBr 3 nanolasers can be potentially deposited on arbitrary surfaces, which makes them a versatile tool for integration with various on -chip systems.