One-Dimensional Carrier Confinement in 'Giant' CdS/CdSe Excitonic Nanoshells
| Autor: | Holly Eckard, Natalia Razgoniaeva, Alexander N. Tarnovsky, Mikhail Zamkov, Darya S. Budkina, Marissa Augspurger, Mingrui Yang, Dmitriy Khon, Pavel Moroz |
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| Rok vydání: | 2017 |
| Předmět: |
Band gap
business.industry Chemistry Exciton Shell (structure) Nanoparticle 02 engineering and technology General Chemistry Narrow-gap semiconductor 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Biochemistry Catalysis Nanoshell 0104 chemical sciences Condensed Matter::Materials Science Colloid and Surface Chemistry Quantum dot Optoelectronics 0210 nano-technology business Bohr radius |
| Zdroj: | Journal of the American Chemical Society. 139:7815-7822 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | The emerging generation of quantum dot optoelectronic devices offers an appealing prospect of a size-tunable band gap. The confinement-enabled control over electronic properties, however, requires nanoparticles to be sufficiently small, which leads to a large area of interparticle boundaries in a film. Such interfaces lead to a high density of surface traps which ultimately increase the electrical resistance of a solid. To address this issue, we have developed an inverse energy-gradient core/shell architecture supporting the quantum confinement in nanoparticles larger than the exciton Bohr radius. The assembly of such nanostructures exhibits a relatively low surface-to-volume ratio, which was manifested in this work through the enhanced conductance of solution-processed films. The reported core/shell geometry was realized by growing a narrow gap semiconductor layer (CdSe) on the surface of a wide-gap core material (CdS) promoting the localization of excitons in the shell domain, as was confirmed by ultrafast transient absorption and emission lifetime measurements. The band gap emission of fabricated nanoshells, ranging from 15 to 30 nm in diameter, has revealed a characteristic size-dependent behavior tunable via the shell thickness with associated quantum yields in the 4.4-16.0% range. |
| Databáze: | OpenAIRE |
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