| 1. |
- Batili, Hazal
(författare)
-
Synthesis, Electrophoretic Deposition, and Characterization of Nanostructured Thermoelectric Materials
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The world’s increasing demand for energy and supplying this energy dominantlyfrom fossil fuels has a major impact on global climate change. Theenergy crisis has gotten more alarming in the recent years which increasedthe motivation for replacing fossil fuels with greener routes for energy harvest.There are various technologies developed for harvesting energy, andthe ability to recover energy from waste heat at a wide range of temperatures (from room temperature to more than 1000 ∘C) distinguished thethermoelectric (TE) materials from the rest. The drawback about the thermoelectricdevices is that they are too inefficient to be cost-effective in manyapplications, and the developments in nanotechnology is providing somesolutions to increase the efficiency of these materials and devices.The field of thermoelectrics suffer from large discrepancy of theresults in the literature, which is generally attributed to the variations inthe materials qualities, urging a need for the development of synthetictechniques that can lead to large-scale TE materials in reasonable timeframe. In this thesis, three different routes for rapid, scalable, and energyefficient, wet-chemical synthetic techniques for bismuth chalcogenidecompounds are presented. Microwave assisted heating during reactionprovided better control over the particle properties while reducing thereaction time and carbon footprint of the synthetic method, leading tomaterials bismuth chalcogenides with promising TE transport propertiesin a scalable and reproducible manner.Hybrid TE materials, and recently emerging solid-liquid TE materialsconcept, requires fabrication of porous TE films, to study the effect of variousinterfaces, including solid and liquid electrolytes. For this purpose, wedeveloped and optimized the electrophoretic deposition (EPD) process toprepare nanostructured porous TE films by preserving the size and morphologyof the as-synthesized bismuth chalcogenide particles. A new glass based substrate is designed and fabricated to study the electronic transportproperties of the electrically active films prepared via EPD. Using this platform,we could clearly demonstrate the significance of the synthetic methodon the surface chemistry and resultant transport properties of the TE materials.The methods and materials developed in this thesis are expected toimpact and expedite further developments in the field of thermoelectrics.
|
|
| 2. |
- Liscio, Andrea, et al.
(författare)
-
Local Surface Potential of pi-Conjugated Nanostructures by Kelvin Probe Force Microscopy: Effect of the Sampling Depth
- 2011
-
Ingår i: SMALL. - : John Wiley and Sons, Ltd. - 1613-6810. ; 7:5, s. 634-639
-
Tidskriftsartikel (refereegranskat)abstract
- Kelvin probe force microscopy (KPFM) is usually applied to map the local surface potential of nanostructured materials at surfaces and interfaces. KPFM is commonly defined as a surface technique, even if this assumption is not fully justified. However, a quantification of the surface sensitivity of this technique is crucial to explore electrical properties at the nanoscale. Here a versatile 3D model is presented which provides a quantitative explanation of KPFM results, taking into account the vertical structure of the sample. The model is tested on nanostructured films obtained from two relevant semiconducting systems for field-effect transistor and solar cell applications showing different interfacial properties, i.e., poly(3-hexylthiophene) (P3HT) and perylene-bis-dicarboximide (PDI). These findings are especially important since they enable quantitative determination of the local surface potential of conjugated nanostructures, and thereby pave the way towards optimization of the electronic properties of nanoscale architectures for organic electronic applications.
|
|
| 3. |
- Liu, Tianjun, et al.
(författare)
-
High Responsivity Circular Polarized Light Detectors based on Quasi Two-Dimensional Chiral Perovskite Films
- 2022
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 16:2, s. 2682-2689
-
Tidskriftsartikel (refereegranskat)abstract
- Circularly polarized light (CPL) has considerable technological potential, from quantum computing to bioimaging. To maximize the opportunity, high performance photodetectors that can directly distinguish left-handed and right-handed circularly polarized light are needed. Hybrid organic- inorganic perovskites containing chiral organic ligands are an emerging candidate for the active material in CPL photo-detecting devices, but current studies suggest there to be a trade-off between the ability to differentially absorb CPL and photocurrent responsivity in chiral perovskites devices. Here, we report a CPL detector based on quasi two-dimensional (quasi-2D) chiral perovskite films. We find it is possible to generate materials where the circular dichroism (CD) is comparable in both 2D and quasi-2D films, while the responsivity of the photodetector improves for the latter. Given this, we are able to showcase a CPL photodetector that exhibits both a high dissymmetry factor of 0.15 and a high responsivity of 15.7 A W-1. We believe our data further advocates the potential of chiral perovskites in CPL-dependent photonic technologies.
|
|
| 4. |
- Martin, Cristina, et al.
(författare)
-
Metal-biomolecule frameworks (BioMOFs) : a novel approach for "green" optoelectronic applications
- 2022
-
Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 58:5, s. 677-680
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, a water-stable microcrystalline bioMOF was synthesized, characterized, and loaded with silver ions or highly emissive rare earth (RE) metals such as Eu3+/Tb3+. The obtained materials were used as active layers in a proof-of-concept sustainable light-emitting device, highlighting the potential of bioMOFs in optoelectronic applications.
|
|
| 5. |
- Pecunia, Vincenzo, et al.
(författare)
-
Roadmap on energy harvesting materials
- 2023
-
Ingår i: Journal of Physics. - : IOP Publishing. - 2515-7639. ; 6:4
-
Tidskriftsartikel (refereegranskat)abstract
- Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere.
|
|
| 6. |
- Trifiletti, Vanira, et al.
(författare)
-
Bismuth-Based Perovskite Derivates with Thermal Voltage Exceeding 40 mV/K
- 2024
-
Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455.
-
Tidskriftsartikel (refereegranskat)abstract
- Heat is an inexhaustible source of energy, and it can be exploited by thermoelectronics to produce electrical power or electrical responses. The search for a low-cost thermoelectric material that could achieve high efficiencies and can also be straightforwardly scalable has turned significant attention to the halide perovskite family. Here, we report the thermal voltage response of bismuth-based perovskite derivates and suggest a path to increase the electrical conductivity by applying chalcogenide doping. The films were produced by drop-casting or spin coating, and sulfur was introduced in the precursor solution using bismuth triethylxanthate. The physical-chemical analysis confirms the substitution. The sulfur introduction caused resistivity reduction by 2 orders of magnitude, and the thermal voltage exceeded 40 mV K-1 near 300 K in doped and undoped bismuth-based perovskite derivates. X-ray diffraction, Raman spectroscopy, and grazing-incidence wide-angle X-ray scattering were employed to confirm the structure. X-ray photoelectron spectroscopy, elemental analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were employed to study the composition and morphology of the produced thin films. UV-visible absorbance, photoluminescence, inverse photoemission, and ultraviolet photoelectron spectroscopies have been used to investigate the energy band gap.
|
|
