Reversible Charge-Carrier Trapping Slows Förster Energy Transfer in CdSe/CdS Quantum-Dot Solids
| Autor: | Montanarella, Federico, Biondi, Margherita, Hinterding, Stijn O.M., Vanmaekelbergh, Daniel, Rabouw, Freddy T., Sub Condensed Matter and Interfaces, Sub Soft Condensed Matter, Sub Inorganic Chemistry and Catalysis, Condensed Matter and Interfaces, Inorganic Chemistry and Catalysis |
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| Přispěvatelé: | Sub Condensed Matter and Interfaces, Sub Soft Condensed Matter, Sub Inorganic Chemistry and Catalysis, Condensed Matter and Interfaces, Inorganic Chemistry and Catalysis |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Photoluminescence
Materials science Physics::Optics Bioengineering 02 engineering and technology Trapping Nanocrystal 010402 general chemistry charge-carrier trapping 7. Clean energy 01 natural sciences Condensed Matter::Materials Science colloidal quantum dot delayed emission General Materials Science Spontaneous emission Condensed Matter::Other Mechanical Engineering Relaxation (NMR) General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 0104 chemical sciences Photoexcitation Quantum dot Chemical physics Charge carrier 0210 nano-technology Förster energy transfer |
| Zdroj: | Nano Letters, 18(9), 5867. American Chemical Society Nano Letters |
| ISSN: | 1530-6984 |
| Popis: | The dynamics of photoluminescence (PL) from nanocrystal quantum dots (QDs) is significantly affected by the reversible trapping of photoexcited charge carriers. This process occurs after up to 50% of the absorption events, depending on the type of QD considered, and can extend the time between the photoexcitation and relaxation of the QD by orders of magnitude. Although many optoelectronic applications require QDs assembled into a QD solid, until now, reversible trapping has been studied only in (ensembles of) spatially separated QDs. Here, we study the influence of reversible trapping on the excited-state dynamics of CdSe/CdS core/shell QDs when they are assembled into close-packed "supraparticles". Time- and spectrally resolved photoluminescence (PL) measurements reveal competition among spontaneous emission, reversible charge-carrier trapping, and Förster resonance energy transfer between the QDs. While Förster transfer causes the PL to red-shift over the first 20-50 ns after excitation, reversible trapping stops and even reverses this trend at later times. We can model this behavior with a simple kinetic Monte Carlo simulation by considering that charge-carrier trapping leaves the QDs in a state with zero oscillator strength in which no energy transfer can occur. Our results highlight that reversible trapping significantly affects the energy and charge-carrier dynamics for applications in which QDs are assembled into a QD solid. |
| Databáze: | OpenAIRE |
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