• Title/Summary/Keyword: Cesium lead halide

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Anion Exchange Reaction Dynamics in Cesium Lead Halide Perovskite Quantum Dots (Cesium Lead Halide 페로브스카이트 양자점의 음이온 교환 반응 동역학)

  • Lee, See Maek;Jung, Hyunsung;Park, Woonik;Lim, Hyunseob;Bang, Jiwon
    • Journal of the Korean institute of surface engineering
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    • v.51 no.5
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    • pp.257-262
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    • 2018
  • Cesium lead halide perovskite quantum dots (QDs) have recently emerged as highly promising opto-electronic materials. Despite the relative facile anion exchange reactions in cesium lead halide perovskite QDs, in depth study of the anion exchange reactions such as reaction kinetics are required that can provide insight into the crystal transformation in the cesium lead halide perovskite QDs. Herein, we investigated the anion exchange reaction from $CsPbI_3$ QDs to $CsPbBr_3$ QDs with varying the particle size of the starting $CsPbI_3$ QDs. By characterizing the PL spectra in the anion exchange reaction process, we observed that discontinuous PL peak shifts during I-to-Br anion exchange reaction in starting $CsPbI_3$ QDs over a critical size. Origin of the discontinuous I-to-Br anion exchange kinetics are mainly due to thermodynamically unstable nature of the $CsPb(Br/I)_3$ alloy QDs.

Controlling Quantum Confinement and Magnetic Doping of Cesium Lead Halide Perovskite Nanocrystals

  • Dong, Yitong;Parobek, David;Son, Dong Hee
    • Journal of the Korean Ceramic Society
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    • v.55 no.6
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    • pp.515-526
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    • 2018
  • Cesium lead halide ($CsPbX_3$) nanocrystals have emerged as a new family of semiconductor nanomaterials that can outperform existing semiconductor nanocrystals owing to their superb optical and charge transport properties. Although these materials are expected to have many superior properties, control of the quantum confinement and isoelectronic magnetic doping, which can greatly enhance their optical, electronic, and magnetic properties, has faced significant challenges. These obstacles have hindered full utilization of the benefits that can be obtained by using $CsPbX_3$ nanocrystals exhibiting strong quantum confinement or coupling between exciton and magnetic dopants, which have been extensively explored in many other semiconductor quantum dots. Here, we review progress made during the past several years in tackling the issues of introducing controllable quantum confinement and doping of $Mn^{2+}$ ions as the prototypical magnetic dopant in colloidal $CsPbX_3$ nanocrystals.

Structural, morphological, optical, and photosensing properties of Cs2TeI6 thin film synthesized by two-step dry process

  • Hoat, Phung Dinh;Van Khoe, Vo;Bae, Sung-Hoon;Lim, Hyo-Jun;Hung, Pham Tien;Heo, Young-Woo
    • Journal of Sensor Science and Technology
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    • v.30 no.5
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    • pp.279-285
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    • 2021
  • Recently, cesium tellurium iodine (Cs2TeI6) has emerged as an inorganic halide perovskite material with potential application in optoelectronic devices due to its high absorption coefficient, suitable bandgap and because it consists of nontoxic and earth-abundant elements. However, studies on its fabrication process as well as photoresponse characteristics are limited. In this study, a simple and effective method is introduced for the synthesis of Cs2TeI6 thin films by a two-step dry process. A Cs2TeI6-based lateral photosensor was fabricated, and its photoresponse characteristics were explored under laser illuminations of four different wavelengths in the visible range: 405, 450, 520, and 655 nm. The initial photosensing results suggest potential application and can lead to more promising studies of Cs2TeI6 film in optoelectronics.

Technology Development Trends of Cesium Lead Halide Based Light Emitting Diodes (세슘납할로겐화물 페로브스카이트 기반 LED 기술개발 동향)

  • Pyun, Sun Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.12
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    • pp.737-749
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    • 2016
  • Recently perovskite materials with much cheaper cost and marvellous optoelectronic properties have been studied for next generation LED display devices overseas. Technology development trends of inorganic $CsPbX_3$(X=halogen) based LEDs (PeLEDs) with assumed high stability were investigated on literature worldwide. It was found that syntheses methods of these nanocrystals (NCs, mainly quantum dots, QDs) made great progress. A new room temperature synthesis method showed outstanding PL (photoluminescence) properties such as high quantum yield (QY), narrow emission width, storage stability comparable with, or often exceeding those of conventional hot injection method and CdSe@ZnS type inorganic colloidal QDs. PeLEDs with shell layers might be more promising, indicating urgent real research start of this solution processing technology for small businesses in Korea.

Effect of Heat and Moisture on the Phase Transition in Dimethylammonium-Facilitated CsPbI3 Perovskite (다이메틸암모늄 유도 CsPbI3 페로브스카이트 상의 상전이 거동에 대한 열과 수분의 영향)

  • Sohyun Kang;Seungmin Lee;Jun Hong Noh
    • Korean Journal of Materials Research
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    • v.33 no.8
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    • pp.344-351
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    • 2023
  • Cesium lead iodide (CsPbI3) with a bandgap of ~1.7 eV is an attractive material for use as a wide-gap perovskite in tandem perovskite solar cells due to its single halide component, which is capable of inhibiting halide segregation. However, phase transition into a photo inactive δ-CsPbI3 at room temperature significantly hinders performance and stability. Thus, maintaining the photo-active phase is a key challenge because it determines the reliability of the tandem device. The dimethylammonium (DMA)-facilitated CsPbI3, widely used to fabricate CsPbI3, exhibits different phase transition behaviors than pure CsPbI3. Here, we experimentally investigated the phase behavior of DMA-facilitated CsPbI3 when exposed to external factors, such as heat and moisture. In DMA-facilitated CsPbI3 films, the phase transition involving degradation was observed to begin at a temperature of 150 ℃ and a relative humidity of 65 %, which is presumed to be related to the sublimation of DMA. Forming a closed system to inhibit the sublimation of DMA significantly improved the phase transition under the same conditions. These results indicate that management of DMA is a crucial factor in maintaining the photo-active phase and implies that when employing DMA designs are necessary to ensure phase stability in DMA-facilitated CsPbI3 devices.