Perovskites have emerged as promising materials for PV applications due to their high efficiency, low cost, and tuneable bandgap. However, perovskites are susceptible to degradation under ambient conditions, leading to a decrease in solar cell performance over time. Degradation is caused by water vapour and oxygen presence in the ambient environment as well as by illumination. The effect of...
With the rise of nanostructured photovoltaics came the need for characterisation of photovoltaic properties on the nanoscale. The best candidate to fulfil this need is, in many cases, scanning probe microscopy (SPM), and for electrical characterisation, current-detecting AFM (C-AFM) is the natural candidate of choice.
During any current-detecting AFM measurement, we detect current that flows...
Plasmonic or generally nanophotonic systems have been usually investigated by optical and electron beam spectroscopic methods. However, as a rule, each of them has been applied for individual samples separately without direct comparison of their results. We take up this challenge and report on the correlative electron and optical spectroscopy applied for an exploration of fundamental phenomena...
The electrochemical systems for energy storage with aqueous electrolytes have attracted significant attention mainly due to their high safety, ionic conductivity, and lower costs in comparison to organic-based electrolytes. They also offer non-flammability, good recyclability, and environmental friendliness that presents them as a promising alternative for large-scale energy storage...
The nanorod-nanorod contact represents a fundamental element of chemiresistive semiconducting metal oxide nanonetwork-based gas sensors. The enhancement of sensing capabilities is thought to be a consequence of the potential barriers that form at the nanorod-nanorod interface, with the height of the barriers being strongly influenced by the adsorption and desorption of the detected gas....
Motivation: Current silicon-based production methods for modern energy-harvesting systems and other electronics fall short of low-cost fabrication requirements. The future of commercializing flexible and printed electronics lies in rapid, cost-effective roll-to-roll manufacturing, which necessitates the use of flexible, inexpensive substrates like PET, PEN, and, more recently, eco-friendly...
Digital holographic microscopy is a powerful tool for characterizing all-dielectric optical metasurfaces. Its ability to reconstruct amplitude and phase offers insight into the scattered-light wavefront shaping. While dielectric optical metasurfaces have garnered significant interest recently, the absence of an extensive library of building blocks based on real-world experimental data is...
Metal halide perovskites (MHPs) have garnered significant scientific interest due to their outstanding optoelectronic properties and high efficiencies in solar cell photoconversion. The development of MHPs has relied primarily on solution-based methods as the growth techniques. Although physical vapor deposition (PVD) techniques have been explored less (with the exception of co-evaporation),...
The advancement of electronics in recent decades caused a sudden demand for new materials suitable for data processing. A notable focus has emerged in the field of optoelectronics, which utilizes light for processing information. This trend has heightened interest in materials capable of responding effectively to incoming light pulses.
Bismuth vanadate (BiVO4) nanoparticles were modified...
Janus 2D TMD is formed by two different chalcogen atoms on each side of the TMD (represented as Janus XMY, where M = transition metal; X = chalcogen at the bottom; Y = chalcogen at the top), and due to this out-of-plane break mirror symmetry and electronegativity difference between top and bottom layers, Janus TMD has internal perpendicular electric field, which leads to a variety of novel...
Great attention has been drawn to the manipulation of ultraviolet (UV) light because of its application in the telecommunication and consumer electronics industry, where extreme-UV lithography is a primary workhorse. However, absorption and tight precision constraints set limits on the fabrication of optical components, such as lenses, suitable for this part of the spectra. Nanophotonics...
The isolation of graphene in 2004 raised an enormous excitement in the community, bringing to light a fundamentally new class of low-dimensional materials. Soon after, the graphene's insulating cousin – hexagonal boron nitride – was introduced, initiating a burst of papers speculating about a new electronics era. Process scalability, which is necessary for the utilization of 2D materials on a...
The electronic characteristics of graphene undergo significant alterations depending on the structure and dimensions of its layers. Furthermore, in applications involving graphene, the manipulation of electronic states can be achieved through interactions with adsorbed species and by introducing atoms and molecules between graphene and the substrate, forming what is known as the van der Waals...
The silicon-vacancy (SiV) color center is a light-emitting crystallographic point defect with a narrow zero phonon line (ZPL) at 738 nm and a high Debye-Waller factor of 70%. The SiV center can be fabricated in polycrystalline diamond (PCD) thin films by the chemical vapor deposition (CVD) technique. PCD films with SiV centers emerged as promising candidates for applications in sensing,...
Investigation of Particle-Plasmon Fields with a Tip and Structured Light
L. Huber*, H. Ditlbacher, U. Hohenester, J. Krenn
Institute for Physics, University of Graz, Universitätsplatz 5, 8010 Graz, Austria
* lorenz.huber@edu.uni-graz.at
We present a combined experimental and theoretical analysis for the mapping of plasmonic nearfields using an apertureless SNOM-tip and a...
The exceptional optoelectronic features of perovskite thin films for next-generation solar cells are drawing significant interest, but maintaining their stability over time under operating conditions remains a critical challenge. We investigated the degradation mechanisms of Methylammonium Lead Iodide (MAPI) perovskite thin films, using AFM in controlled nitrogen atmospheres. Based on prior...
Vanadium dioxide (VO2) is a material that exhibits an insulator-to-metal transition, which is accompanied by an abrupt change in its optical properties. The VO2 nanostructures can thus support both dielectric (Mie-type) and plasmonic resonances in the same spectral range, which can be switched by applied temperature. Furthermore, the optical response of the nanostructures can be tuned by...
We report on modeling the signal of micro-focused Brillouin light scattering (BLS) on spin waves. Our model can use either analytic calculation of the induced susceptibility for quick optimization of simple systems such as infinite thin films, or it can use results of micromagnetic simulations for thorough analysis of systems with complicated geometries and compositions. We apply this model to...
Cesium lead bromide (CsPbBr3) has attracted significant attention [1] for its exceptional optoelectronic properties, including high photoluminescence yield [2] and low non-radiative lifetimes [3]. Additionally, its cost-effective synthesis methods [4] make it particularly promising for applications in light-harvesting devices like photovoltaics [5] and radiation detection [6]. However,...
All-inorganic, as well as organic-inorganic hybrid halide perovskites are one of the most promising class of semiconductors for new generation of energy conversion and optoelectronic applications. While there has been tremendous technological progress in device development, especially in the field of perovskite solar cells, the advancement of the knowledge of fundamental photophysical...
Vortex electron beams (VEBs) are a class of chiral free electron states carrying orbital angular momentum (OAM). Right-handed and left-handed VEBs, acting as probes, can interact differently with chiral objects, yielding measurably different results in electron energy-loss spectroscopy (EELS) experiments. This nontrivial behavior is usually referred to as dichroism. We present a theoretical...
Electron deficit diketopyrrolopyrrole (DPP) functionalised with an electron donating unit acts as a donor-acceptor molecule, offering conveniently tunable spectroscopic properties. DPPs have proven success in dye application and shown potential for use in photovoltaics. Understanding the photophysical properties is crucial for their application as organic materials, especially in the near IR...
Our study deals with experimental and theoretical research on the plasmonic lightning-rod effect. Electron energy loss spectroscopy has been used to investigate the electromagnetic response of plasmonic antennas and to study the impact of the curvature of their surfaces on the local enhancement of an electromagnetic field. A systematic growth of the field enhancement with the increasing local...
This study investigates post-synthesis band gap tuning of CsPbBr3 nanocrystals through halide anion exchange (HAE) with CsI. While effective HAE occurs, phase segregation leads to Br-rich core and I-rich shell formations, impacting optical properties. Comprehending these phenomena enhances the development of precise optoelectronic engineering strategies tailored for semiconductor...
Membrane models are a versatile tool for understanding the fundamental mechanisms of cellular function. Their applications range from the modelling of complex biological processes and protein characterization to the development of biosensors and drug delivery systems.
This work deals with cellular membrane model preparation on microfluidic devices.
It focuses on free-standing planar lipid...
This work deals with the design, fabrication and verification of microfluidic chips that can be used to sort particles using surface acoustic and standing surface acoustic waves. The sorting function of this chip is based on the piezoelectric properties of the substrate. For this reason, lithium niobate was selected as the substrate. The acoustic waves are generated by interdigital transducers...
The Nobel Prize awarded to Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura in 2014 propelled III-Nitride semiconductors into the spotlight, marking the advent of third-generation semiconductors and sparking a revolution in lighting. My studies from graduate to post-PhD explored the multiple applications of III-Nitride materials, including solar cells, bio-sensing, and the realization of...
The development of light detectors is focused on high performance, fast response and simple fabrication. These parameters are affected by the charge carrier mobility, which is sensitive to perturbations in the crystal lattice, namely defects and phonons. Gallium nitride is a polar III-V semiconductor, where a strong interaction between free electrons and phonons is observed. The interaction...
Modification of laser beams spatial intensity distribution with the Spatial Light Modulator (SLM) for the purpose of electron beams modification control via the ponderomotive force
Low Energy Ion Scattering spectroscopy (LEIS) analysis of bismuth selenide (Bi2Se3), a strong 3D topological insulator, revealed oscillations of the detected signal in dependence on primary ion beam energy.
Bismuth is a part of the group of elements where oscillatory behaviour was already noticed, such as gallium, indium or lead. Generally, it is ascribed to quasi-resonant charge exchange...
The ongoing intensive research in the field of electrical discharges in or with water is fueled both by the many unsolved problems concerning the mechanism of such complex discharges and by the possible new applications of plasma-activated water (PAW) related to water decontamination and environmentally friendly synthesis of fertilizers in plasma-assisted agriculture. A nanosecond DBD-like...
Pb$_{1-x}$Ge$_x$Te and Pb$_{1-x}$Sn$_x$Te are novel pseudo-binary alloys that are widely studied for their reversible ferroelectric phase transition between cubic O$_h$ and rhombohedral C$_{3v}$ structures at temperatures above and below the phase transition, accompanied by anomalies in properties like resistivity and specific heat. The transition temperature T$_c$ can be tuned by varying the...
In recent years, the study of synaptic plasticity has garnered significant attention for its crucial role in the functioning of the nervous system and its implications in learning and memory. This research explores the synaptic plasticity of heptazine-modified bismuth vanadate (BiVO4), with potential applications in neuromorphic computing and memory devices. The modification of BiVO4 with...
Stainless steel is widely used in our daily life due to a unique combination of high corrosion resistance and excellent mechanical properties. Despite its importance, there is a lack of surface science characterization of stainless steels due to the absence of suitable single crystals. Here we use steel single crystals with a composition of 70% Fe, 15% Ni and 15% Cr [1] to demonstrate that...
Casimir self-assembly (CaSA) of micron-sized gold flakes in aqueous solutions at room temperature forms Fabry-Pérot resonators with separation distances of about 100–220 nm and tunable optical responses in the visible spectral range. This study investigates thermal fluctuations, manifested as vertical fluctuations of flakes around their equilibrium position. Using optical microscopy and...
Perovskite solar cells (PVKSC) are currently being intensively researched due to their promising efficiency in generating electricity from the sun. PVKSCs seem to be a real alternative to classic silicon-based cells. Scientists around the world are trying to modify individual components of perovskite cells to achieve the highest possible efficiency. One of the active substances currently used...
Zintl compounds with a rare-earth element (Eu) have been known to present fascinating properties such as colossal magnetoresistance, thermoelectric phenomena, and magnetic topological states, which involves the valence of the rare-earth cations surrounded by polyanionic chains [1–3]. In this study, we achieved the growth of rare-earth Zintl phase shells on InAs nanowires by molecular beam...
Structural color filters use nano-sized elements to allow for selective transmission of the incident light. Compared to the traditional, pigment- and dye-based color filters, they offer a cheaper, less environmentally harming and more scalable alternative of color filtering. However, their structural nature makes them very sensitive to the illumination direction and leads to spectral shifts in...
