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- Fresch, Elisa, et al.
(författare)
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Two-dimensional electronic spectroscopy
- 2023
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Ingår i: Nature Reviews Methods Primers. - 2662-8449. ; 3:1
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Forskningsöversikt (refereegranskat)abstract
- Two-dimensional electronic spectroscopy (2DES) is a popular technique that can track ultrafast coherent and incoherent processes in real time. Since its development in the late 1990s, 2DES has become a powerful tool for investigating ultrafast dynamics in a range of systems, including nanomaterials and optoelectronic devices. This Primer explains the underlying physical principles of 2DES and how it can be applied to study dynamic photophysical processes. The article discusses how to collect, process and analyse data, with a summary of currently available experimental configurations. Common issues and challenges are considered, focusing on the limitations and reproducibility of the technique, finishing with an exploration of potential future advances and applications.
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- Zhao, Haiguang, et al.
(författare)
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Gram-scale synthesis of carbon quantum dots with a large Stokes shift for the fabrication of eco-friendly and high-efficiency luminescent solar concentrators
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 14:1, s. 396-406
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Tidskriftsartikel (refereegranskat)abstract
- Luminescent solar concentrators (LSCs) are large-area sunlight collectors coupled to small area solar cells, for efficient solar-to-electricity conversion. The three key points for the successful market penetration of LSCs are: (i) removal of light losses due to reabsorption during light collection; (ii) high light-to-electrical power conversion efficiency of the final device; (iii) long-term stability of the LSC structure related to the stability of both the matrix and the luminophores. Among various types of fluorophores, carbon quantum dots (C-dots) offer a wide absorption spectrum, high quantum yield, non-toxicity, environmental friendliness, low-cost, and eco-friendly synthetic methods. However, they are characterized by a relatively small Stokes shift, compared to inorganic quantum dots, which limits the highest external optical efficiency that can be obtained for a large-area single-layer LSC (>100 cm2) based on C-dots below 2%. Herein, we report highly efficient large-area LSCs (100–225 cm2) based on colloidal C-dots synthesized via a space-confined vacuum-heating approach. This one batch reaction could produce Gram-scale C-dots with a high quantum yield (QY) (∼65%) using eco-friendly citric acid and urea as precursors. Thanks to their very narrow size distribution, the C-dots produced via the space-confined vacuum-heating approach had a large Stokes shift of 0.53 eV, 50% larger than C-dots synthesized via a standard solvothermal reaction using the same precursors with a similar absorption range. The large-area LSC (15 × 15 × 0.5 cm3) prepared by using polyvinyl pyrrolidone (PVP) polymer as a matrix exhibited an external optical efficiency of 2.2% (under natural sun irradiation, 60 mW cm−2, uncharacterized spectrum). After coupling to silicon solar cells, the LSC exhibited a power conversion efficiency (PCE) of 1.13% under natural sunlight illumination (20 mW cm−2, uncharacterized spectrum). These unprecedented results were obtained by completely suppressing the reabsorption losses during light collection, as proved by optical spectroscopy. These findings demonstrate the possibility of obtaining eco-friendly, high-efficiency, large-area LSCs through scalable production techniques, paving the way to the lab-to-fab transition of this kind of devices.
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