Spectrally stable blue perovskite light-emitting diodes
Feng Gao (IFM), Mats Fahlman (ITN), Heyong Wang (IFM) Qingqing Wang (ITN)
Light-emitting diodes (LEDs) have great advantage of efficiently converting electricity into light, notably reducing energy consumption in the lighting and display products. Recently, metal halide perovskites have gained significant attention due to their outstanding optoelectronic properties and solution processability. So far, green, red and infrared perovskite LEDs have progressed rapidly with external quantum efficiencies reaching over 20%. However, blue perovskite LEDs still face key challenges of low efficiency and poor color stability.In this project, we aim to solve the key challenges lying in blue perovskite LEDs and to develop efficient and spectrally stable blue perovskite LEDs by exploiting new two-dimensional perovskites. Compared with three-dimensional perovskites, two-dimensional perovskites have largely increased exciton binding energies due to the multiple-quantum-well electronic structures, and thus show increasing bandgap with narrowing width of the “well”. They employ the quantum confinement effect to tune the emission colors of the blue perovskites, avoiding the use of spectrally unstable mixed halide perovskites. As a result, two-dimensional perovskites offer new opportunities for preparing high-performance and spectrally stable blue perovskite LEDs.
Combining nanoporous transition metal oxides and conducting polymers for electrolytic hydrogen peroxide synthesis
Zhixing Wu (IFM), Mikhail Vagin (IFM), Penghui Ding (ITN), Emma Björk (IFM), Xavier Crispin (ITN)The project is dedicated to the elaboration of the noble metal free device for electrosynthesis of H2O2 from air and water only. The combination of two half-cell reactions (namely, oxygen evolution reaction (OER) and oxygen reduction reaction (ORR)) into unified device manifests the mutual integration of two PhD projects. The new nanoporous OER electrocatalysts based on transition metal oxides will be obtained by a hydrothermal synthesis with a nanoscale porosity control. The conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) will be synthesized and utilized for H2O2 electrosynthesis by ORR.
Catalytically active, corrosion resistant multicomponent nanostructured coatings
Per Eklund (IFM), Smita Rao (IFM), Clara Linder (IFM), Emma Björk (IFM)
Multicomponent alloys typically include ~4 or more principal elements and exhibit unique chemical and physical properties. The concept includes but is not limited to so-called high-entropy alloys (HEAs), which is a subset of multicomponent systems where high entropy of mixing (ΔSmix), or kinetic effects, stabilize a single-phase solid solution (Fig. 1). They offer opportunities for tailoring coating materials resilience and corrosion resistance, enabling exceptionally corrosion-resistant substrate materials such as nickel, steels and other alloys, while retaining good electrical properties. The challenge in the battery area is to develop an economic and industrially scalable process of a corrosion-resistant multicomponent coating, that can also act as a catalyst in alkaline media. For fuel-cell contact plates, the demands on corrosion-resistance are similar to those in industrial batteries, but in different chemical environments and operating temperatures; at low pH up to150 °C for PEM fuel cells (polymer electrolyte membrane) used in vehicles.
In this CeNano proposal, the materials science of novel multicomponent metallic and nitride alloy coatings will be investigated. The aim will be to combine electrocatalytic activity and corrosion resistance in one coating material. The overall longer-term research objective is to develop novel high-performance physically vapor deposited (PVD) multicomponent CrFeNi-based coatings that are both highly corrosion-resistant (Fig. 1b) and electrocatalytically active for applications in industrial batteries and fuel cells.
The importance of gas flow directions in surface-controlled deposition of nanometer thin films
Henrik Pedersen (IFM), Matts Karlsson (IEI), Polla Rouf (IFM), Anton Persson (IEI)
IEI-Applied Thermodynamics and Fluid Mechanics
Nanometer thin films of materials play a crucial role in all modern nano-scaled electronic devices. The method for materials synthesis offering the highest level of control on the sub-nanometer scale is atomic layer deposition (ALD), where volatile precursor molecules, containing the atoms needed for the film material are introduced in a deposition chamber in pulses separated by inert gas purges. The time-resolved precursor supply renders a self-limiting surface chemistry – chemical reactions stops when all surface sites are occupied. This makes ALD fully surface-controlled and allows for deposition of conformal films on topographically complex surfaces. It has, however, formed the common notion that ALD simply need enough molecules arriving at the surface, regardless of which direction the molecules came from. We have recently shown that this is notion is not holding up when tested carefully. This project aims at exploring the importance of gas flow directions in ALD and bring a higher level of understanding to the field of materials synthesis at the sub-nanometer scale. The project will create a digital twin of the ALD reactor that will allow studies of gas flows combined with chemical models to study the distribution of chemical species. Experiments will then be designed and performed both digitally and experimentally to verify the modelling. An improved understanding of the role of gas flow directions in what is pictured as fully surface-controlled materials synthesis will significantly add to the general understanding of the ALD technology. It will also and aid in the upscaling of ALD processes for production and aid in improving the usage of the precursor dose in ALD. The project is thus envisioned to contribute to more sustainable manufacturing of nano-scaled electronics.
Highly Efficient Nano-Carrier for Drug Delivery Aiming at Cancer Treatment
Xin Zhang (IFM), Julia Uffenord (IKE), Kajsa Uvdal (IFM), Karin Roberg (IKE)
Cancer of the head and neck is the sixth most common form of cancer worldwide with about 1300 new cases per year in Sweden. Head and neck squamous cell carcinomas (HNSCC) often show resistance to treatments and the 5-year survival rate is merely 60%. Thus, there is a paramount need for assessment of new targets for treatment. In this project, HNSCC cell lines that we have established from the tumor biopsies are used for the evaluation of therapies and characterization of tumor cell properties. The main aim of these studies is to fabricate a highly efficient nanocarrier for conventional anti-cancer drug Cis-platin (CP), providing possibilities for the development of novel therapies for head and neck cancers. To improve the treatment efficiency and reduce side effects in cancer therapy, accurate diagnosis of cancer cell types at a molecular level is highly desirable, while simultaneously minimizing toxicity and maximizing the drug efficacy. Most antibody-based drugs, however, do not enter cells readily without proper formulation and/or delivery vehicles target the cell surface or secreted the proteins, significantly limiting their potential applications. Therefore, a major challenge in current drug-based therapy is to develop highly effective intracellular drug delivery strategies that enable the rapid cellular uptake, minimal endolysosomal trapping, and precise targeting, as many therapeutic targets are inaccessible to current methods.
In our previous CeNano project, we have demonstrated a bio-compatible/-degradable molecule-doped silica nanoparticles (SiNPs) nano-platform (5-90 nm), on which the diverse organic dyes/biomolecules can be installed simultaneously in a single nanoparticle. This facile integration of dyes/molecules in a single particle shows huge potentials in the construction of the drugs for cancer diagnosis and therapy. Therefore, in this project, to realize the proposed purpose (fluorescent Anti-cancer SiNPs (AC-SiNPs)), the following key works (Figure 1) will be gradually done: 1) the fabrication of cancer pro-drug of CP (Pro-CP) with trialkoxysilane that can covalently link to the core functional NPs; 2) the construction of bio-degradable SiNPs core with the highly fluorescent component (DTPA, aggregation-induced red emissive organic dye) that enables the target imaging; 3) the conjugation of cell-penetrating PDs on the surface that facilitates the penetration of delivery system across the cell membrane; 4) the decoration with antibody cetuximab to the outer surface that enables the precise epidermal growth factor receptor (EGFR)-targeted therapy; 5) the detailed biological testing in vivo and in vitro applications.
Figure 1 Schematic illustration of the fabrication of fluorescent AC-SiNPs, Cetuximab-directed cancer cell accumulation, PDs-facilitated endocytosis-independent cellular uptake, and CP-dominated cancer therapy process.
Optical and Mechanical studies of Bouligand Structures
Niclas Solin (IFM), Samiran Bairagi (IFM), Yusheng Yuan (IFM) Kenneth Järrendahl (IFM)
Within this project we aim to prepare hybrids between hard and soft materials where the hard component is made from InAlN and the soft component is made up from readily available proteins such as hen egg white Lysozyme. Within previous Cenano-projects we have investigated formation of composites between InAlN nanostructures and proteins. The InAlN structures are used as templates where voids can potentially be filled with proteins. The InAlN nanostructures are grown on a rotating substrate resulting a dense coverage of helical InAlN nanopillars, and such structures may display structural colors in the visible range of the spectrum. We now want to optimize the filling process and characterize the resulting materials regarding optical and mechanical properties. In another track we want to investigate if the substrate used for growth of InAlN pillars can be modified by the presence of proteins. We will aim to prepare substrates containing ordered protein structures. As proteins are chiral this chirality may be transferred to the inorganic material by influencing the nucleation stage. Optical characterization will initially be performed by ellipsometry. Mechanical characterization will be performed with nanoindentation. In the longer term, depending on the specific nature of the hybrids that we are able to prepare, we will investigate if InAlN:protein hybrids (functionalized with luminescent dyes) can be used for applications related to devices such as to organic dye lasers or devices capable of emission of circularly polarized light. The activities in the short term (the coming year) will include:
1. Synthesis of InAlN chiral nanostructures grown by DC magnetron sputtering
2. Optical and Mechanical characterization of as grown films
3. Investigation of suitable pathways for protein/organic molecule incorporation
4. Optical and Mechanical characterization of resulting composites
5. Synthesis of InAlN nanostructures grown by DC magnetron sputtering on modified substrates
Photo of an as-prepared InAlN film displaying iridescence (left); SEM image of an as-prepared InAlN film (center); and an SEM-image of an InAlN film infiltrated with protein (right).
Graphene sensor for faster and cheaper determination of dioxins in environmental samples
Marius Rodner (IFM) Andreas Skallberg (IFM), Jens Eriksson (IFM), Kajsa Uvdal (IFM)
Dioxins are a broad class of molecules that belong to the category of extremely toxic Persistent Organic Pollutants. A common source of dioxins is industrial waste incineration, where dioxin emissions and monitoring are required by EU regulations. Currently the taxing process of measuring this pollutant is performed via expensive (>500€) and time-consuming (minimum of 3 days) sampling and sophisticated characterization techniques like gas chromatography and mass spectrometry. Alternative approaches based on e.g. immunoassays have been developed as simpler low-cost alternatives, but they are not sufficiently sensitive to meet the requirements for rapid on-site quantification of dioxins in the environment.
Graphene offers a unique platform for sensing where extremely high sensitivity is a priority, since even minimal chemical interaction can cause noticeable changes in electrical conductivity. In this lab-scale proof-of-concept study we aim to develop a sensor solution based on our epitaxial graphene on SiC sensor platform that allows determination of dioxin concentrations within 1.5 h. Sensor housing and a flow cell for integrating the biochemical solution with the graphene will be fabricated using 3D-printing. The biochemistry will be tailored for the 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD, C12H4Cl4O2) molecule, the most toxic dioxin and the one most critical to detect, interfacing with a specific protein configuration to finally produce a time-resolved and selective conductrometric sensor-readout.
Study of nano-sized borides as grain refiners in additively manufactures aluminum alloys
Freddy Leijon (IEI), Babak Bakhit (IFM), Johan Moverare (IEI) , Grzegorz Greczynski (IFM)
Study of nano-sized borides as grain refiners in additively manufactured aluminium alloys
Metal 3d printing or Additive Manufacturing (AM) is an emerging technology holding enormous potential to transform production from mass- to custom-production, and further also disrupt current supply chains providing more flexible production at site and on-demand.
Apart from productivity, one of the main hurdles to overcome for AM is on the material side. Currently for aluminium only alloys of low to mid strength level are available. The major challenge in development of high strength AM alloys is cracking at solidification during the printing process. This is caused by shrinkage in combination with solidification over a too large temperature interval, with the later becoming larger with increasing content of eutectic alloying elements such as Mg, Cu, and Zn typically required to reach high strength.
In traditional metallurgy, grain refiners (GF) are added to the melt in order to heterogeneously nucleate solidification. This increases the numbers of sites where solidification starts, which promotes melt permeability as solidification transition from columnar to equiaxed which preventing cracking as unsolidified liquid Aluminium now can reach in between solidified areas (grains) and fill as solidification proceeds.
For most wrought aluminium alloys TiB2 is used as GF this is typically added in the form of a master alloy wire which dissolves in the melt and releases TiB2 particles and a small amount of Ti. These particles then act as the first step in solidification nucleation as sites for solidification by reducing surface energy barrier required for solidification to start.
In this project we will investigate nano sized TiB2 particles as GF in aluminium alloys for AM and how their efficiency can be improved by doping with W, Ta, and Hf.
TEM image of Tib2 particle in Aluminium, Philipp Maira, Lukas Kaserera, Jakob Brauna, et al, Microstructure and mechanical properties of a TiB2-modified Al–Cu alloy processed by laser powder-bed fusion. Materials Science and Engineering: A, 2020-09-04
Nanoparticle Based Pilot Samples for Waveguide-Enhanced Neutron Fluorescence Experiments
Anna Du Rietz (IFM), Bela Nagy (IFM), Kajsa Uvdal (IFM), Thomas Ederth (IFM)
The aim of the project is to prepare pilot samples with a well-defined layer of Gd2O3 nanoparticles in a waveguide structure for testing a combination of Prompt Gamma Activation Analysis (PGAA) and Neutron Reflectometry (NR) for in situ monitoring of Gd containing nanoparticles. Within this CeNano project we will develop a robust procedure for depositing Gd2O3 nanoparticles in a well-controlled fashion on a gold surface in preparation for a neutron experiment and optimize the sample structure by simulation. The deposited nanoparticles will be characterized using Atomic Force Microscopy, Scanning Electron Microscopy and X-ray Reflectometry. Future applications of the developed method include monitoring of nanoparticles penetrating model cell membranes.
Figure 1: Schematic illustration of the sample. The Au surface is coated with a thiol self-assembled monolayer (SAM). The Gd2O3 nanoparticles are deposited on or covalently bound to the SAM layer. The Gd atoms convert the incoming neutron radiation to gamma rays.
Magnetic-Nanoparticle mediated manipulation of cells in a hydrogel matrix
Kalle Bunnfors, Michael Jury
Hydrogels encompass a large array of materials that represents its wide range of applications. Soft, water swollen polymer networks are one such type that have found increasing uses in the biomedical field. They are of interest since they can be tailored and modified to act as biocompatible extra-cellular matrix (ECM) mimics, and thus are sometimes used as a precursor to in vivo experiments.
Neutrophils are immune cells that are present in most types of mammals. In humans they circulate the body and scavenge for threats. When a neutrophil encounters/identify something that is classified as a threat it can undergo phagocytosis, degranulation and extracellular traps (NETs). Iron oxide nanoparticles (FeNP) have superparamagnetic properties which can be used in MRI or be manipulated in a magnetic field.
Project: In continuation of the (CeNano 2019) project, we will again use the FeNPs in conjunction with cells within a PEG/Hyaluronan hydrogel system to control the movement and growth of cells Now different sized FeNPs will be explored, as well as functionalization of the particles as proof of concept by coupling fluorophores to the nanoparticles. In further understanding how FeNPs and cells interact, it will open possibilities to apply the method to other cell types. Further, it may allow an element of control of these other cell types, for example, neurons for growing nerves, and osteoblasts for bone growth.
Figure 1: a) experimental setup b) Magnet-induced FeNP fibrils c) Neutrophils on FeNP fibrils