Malte Gather

Malte Gather
University of St Andrews · School of Physics and Astronomy

About

268
Publications
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Publications

Publications (268)
Preprint
Angle-independent, narrowband emission is required for many optoelectronic devices, ranging from high-definition displays to sensors. However, emerging materials for electroluminescent devices, such as organics and perovskites, show spectrally broad emission due to intrinsic disorder. Coupling this emission to an optical resonance reduces the linew...
Preprint
Organic exciton-photon polariton lasers have recently been shown to be remarkable candidates for the realization of efficient sources of coherent light operating at room temperature. While their thresholds are now comparable with conventional organic photon lasers, tuning of molecular conformation and orientation as a means to further enhance their...
Article
Biointegrated intracellular microlasers have emerged as an attractive and versatile tool in biophotonics. Different inorganic semiconductor materials have been used for the fabrication of such biocompatible microlasers but often operate at visible wavelengths ill-suited for imaging through tissue. Here, we report on whispering gallery mode microdis...
Preprint
The use of thermally activated delayed fluorescence emitters and emitters that show preferential horizontal orientation of their transition dipole are two emerging strategies to enhance the efficiency of organic light-emitting diodes. We present the first example of a liquid crystalline multi-resonance thermally activated delayed fluorescent emitte...
Article
Full-text available
Following its association with dyslexia in multiple genetic studies, the KIAA0319 gene has been extensively investigated in different animal models but its function in neurodevelopment remains poorly understood. We developed the first human cellular knockout model for KIAA0319 in RPE1 retinal pigment epithelia cells via CRISPR-Cas9n to investigate...
Article
Exciplexes of individual electron donor and acceptor molecules are a promising approach to utilizing otherwise non-emissive triplet states in optoelectronic applications. In this work, we synthesize a series of bis(terpyridine)...
Article
Full-text available
In organic light‐emitting diodes (OLEDs), horizontal orientation of the emissive transition dipole moment (TDM) can improve light outcoupling efficiency by up to 50% relative to random orientation. Therefore, there have been extensive efforts to identify drivers of horizontal orientation. The aspect ratio of the emitter molecule and the glass‐trans...
Article
With this Special Issue, we would like to celebrate the 60th birthday of Prof. Karl Leo, one of the leading scientists in the field of Organic Electronics (see also the Guest Editorial, article number 2101108). This front cover shows a cube made of six individual laboratory‐sized organic light‐emitting diodes (OLEDs). This OLED‐cube has become an i...
Article
Full-text available
Important dynamic processes in mechanobiology remain elusive due to a lack of tools to image the small cellular forces at play with sufficient speed and throughput. Here, we introduce a fast, interference-based force imaging method that uses the illumination of an elastic deformable microcavity with two rapidly alternating wavelengths to map forces...
Article
Full-text available
As solid‐state light sources based on amorphous organic semiconductors, organic light‐emitting diodes (OLEDs) are widely used in modern smartphone displays and TVs. Due to the dramatic improvements in stability, efficiency, and brightness achieved over the last three decades, OLEDs have also become attractive light sources for compact and “impercep...
Article
Full-text available
Local basement membrane (BM) disruption marks the initial step of breast cancer invasion. The activation mechanisms of force-driven BM-weakening remain elusive. We studied the mechanical response of MCF10A-derived human breast cell acini with BMs of tuneable maturation to physical and soluble tumour-like extracellular matrix (ECM) cues. Traction fo...
Article
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The combination of organics and metals in a composite film holds promise for combining plasmonic interaction with gain and for the realization of epsilon-near-zero (ENZ) metamaterials. In particular, fluorescent organic dyes can be used to compensate the plasmonic losses of a homogenized metal-organic material. Here, we fabricate such films through...
Data
3D model files for use in 3D printing a small, inexpensive fluorescent microscope module (https://www.funjournal.org/wp-content/uploads/2021/01/june-19-124.pdf). Please read the readme file before proceeding with printing. If there are any questions or if you would like some adaptors for use with other microscopes, please contact me at jhhb@st-a...
Article
Full-text available
Three novel donor-acceptor molecules comprising the underexplored pyridazine (Pydz) acceptor moiety have been synthesized and their structural, electrochemical and photophysical properties thoroughly characterized. Combining Pydz with two phenoxazine donor units linked via a phenyl bridge in a meta configuration ( dPXZMePydz ) leads to high reverse...
Article
Full-text available
Conjugated polymer particles are brightly fluorescing and stable materials for live cell imaging. Combination of conjugated polymers with a whispering gallery mode (WGM) resonator allows laser emission from microscale particles. Once internalized by cells, the mode pattern of the laser emission can be used for tagging and tracking, as each laser sp...
Article
Full-text available
Optogenetics allows light-driven, non-contact control of neural systems, but light delivery remains challenging, in particular when fine spatial control of light is required to achieve local specificity. Here, we employ organic light-emitting diodes (OLEDs) that are micropatterned into linear arrays to obtain precise optogenetic control in Drosophi...
Article
Full-text available
Despite widespread interest, ultrathin and highly flexible light-emitting devices that can be seamlessly integrated and used for flexible displays, wearables, and as bioimplants remain elusive. Organic light-emitting diodes (OLEDs) with µm-scale thickness and exceptional flexibility have been demonstrated but show insufficient stability in air and...
Article
Strong light–matter coupling leads to the formation of mixed exciton–polariton states, allowing for a rigorous manipulation of the absorption and emission of excitonic materials. Here, we demonstrate the realization of this promising concept in organic photodetectors. By hybridizing the E11 exciton of semiconducting (6,5) single-walled carbon nanot...
Article
Full-text available
Top‐emitting organic light‐emitting diodes (OLEDs) are of interest for numerous applications, in particular for displays with high fill factors. To maximize efficiency and luminance, molecular p‐doping of the hole transport layer (p‐HTL) and a highly reflective anode contact, for example, made from silver, are used. Atomic layer deposition (ALD) is...
Article
Full-text available
The accurate characterization of thin‐film light emitting diodes (LEDs)—including organic light emitting diodes (OLEDs), perovskite LEDs, and quantum dot LEDs—is crucial to the understanding of the factors that influence their efficiency and thus to the fabrication of LEDs with improved performance and stability. In addition, detailed information a...
Article
Full-text available
Central pattern generators (CPGs) are neural networks that produce rhythmic motor activity in the absence of sensory input. CPGs produce ‘fictive’ behaviours in vitro which parallel activity seen in intact animals. CPG networks have been identified in a wide variety of model organisms and have been shown to be critical for generating rhythmic behav...
Article
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Willin/FRMD6 is part of a family of proteins with a 4.1 ezrin-radixin-moesin (FERM) domain. It has been identified as an upstream activator of the Hippo pathway and, when aberrant in its expression, is associated with human diseases and disorders. Even though Willin/FRMD6 was originally discovered in the rat sciatic nerve, most studies have focused...
Article
Full-text available
Cortical stiffness is an important cellular property that changes during migration, adhesion and growth. Previous atomic force microscopy (AFM) indentation measurements of cells cultured on deformable substrates have suggested that cells adapt their stiffness to that of their surroundings. Here we show that the force applied by AFM to a cell result...
Conference Paper
Electrically pumped emission of light-matter exciton-polaritons is of great fundamental and practical interest but so far suffers from poor efficiency. Here, we present a universal strategy to generate polariton emission from state-of-the-art organic light emitting diodes (OLED). We demonstrate green and red emitting devices reaching an external qu...
Preprint
Despite widespread interest, ultrathin and highly flexible light-emitting devices that can be seamlessly integrated and used for flexible displays, wearables, and as bioimplants remain elusive. Organic light-emitting diodes (OLEDs) with $\mu$m-scale thickness and exceptional flexibility have been demonstrated but show insufficient stability in air...
Article
Full-text available
The contractility of cardiac cells is a key parameter that describes the biomechanical characteristics of the beating heart, but functional monitoring of three-dimensional cardiac tissue with single-cell resolution remains a major challenge. Here, we introduce microscopic whispering-gallery-mode lasers into cardiac cells to realize all-optical reco...
Article
Full-text available
Liquid crystalline materials possess great potential as emitters in organic light‐emitting diodes (OLEDs) due to their self‐assembling property, which may lead to anisotropic films and improved charge transport. Here, the key photophysical properties of the columnar liquid crystalline emitter perylene‐3,4,9,10‐tetracarboxylic tetraethyl ester (PTCT...
Article
Full-text available
Fluorescent proteins have emerged as an attractive gain material for lasers, especially for devices requiring biocompatibility. However, due to their optical properties, integration with distributed feedback (DFB) resonators is not readily achievable. Here, a DFB laser with enhanced green fluorescent protein (eGFP) as the gain material is demonstra...
Preprint
Optogenetics allows light-driven, non-contact control of neural systems, but light delivery remains challenging, in particular when fine spatial control of light is required to achieve local specificity. Here, we employ organic light-emitting diodes (OLEDs) that are micropatterned into linear arrays to obtain precise optogenetic control in Drosophi...
Article
Thus far, research activities of 2D materials in optics, photonics and optoelectronics predominantly focus on micromechanically cleaved or grown nanosheets. Here, we show that high quality liquid-exfoliated nanosheets offer an alternative approach. Starting from well-defined, monolayer rich WS2 dispersions obtained after liquid exfoliation and size...
Article
Full-text available
Organic optoelectronic devices combine high-performance, simple fabrication and distinctive form factors. They are widely integrated in smart devices and wearables as flexible, high pixel density organic light emitting diode (OLED) displays, and may be scaled to large area by roll-to-roll printing for lightweight solar power systems. Exceptionally...
Article
Full-text available
Mechanobiology plays a prominent role in cancer invasion and metastasis. The ability of a cancer to degrade extracellular matrix (ECM) is likely connected to its invasiveness. Many cancer cells form invadopodia—micrometer-sized cellular protrusions that promote invasion through matrix degradation (proteolysis). Although it has been hypothesized tha...
Article
Organic single crystals are of interest for optoelectronic applications due to their highly ordered molecular stacking and small defect concentration, giving the possibility of high mobility and luminescence efficiency. To achieve lasing in large flat single crystals, a simple “pick and place” method of mounting organic single crystals onto distrib...
Article
We report two donor-acceptor (D-A) materials based on a cyanoanthracene acceptor paired with diphenylamine (DPAAnCN) and carbazole (CzAnCN) donor moieties. These compounds show hybrid locally excited (LE) charge-transfer (CT) excited states (HLCT), which we demonstrated through a combined photophysical and computational study. Vacuum-deposited orga...
Article
Organic light‐emitting diodes (OLEDs) can emit light over much larger areas than their inorganic counterparts, offer mechanical flexibility, and can be readily integrated on various substrates and backplanes. However, the amount of light they emit per unit area is typically lower and the required operating voltage is higher, which can be a limitati...
Conference Paper
Orientation of transition dipoles can strongly improve the outcoupling efficiency of or-ganic LEDs (OLEDs). We present two new classes of OLED emitters that may achieve horizontal alignment: columnar liquid crystals and carbon nanotubes.
Preprint
Full-text available
Cell stiffness is a key cellular material property that changes locally and temporally during many cellular functions including migration, adhesion, and growth. Currently, it is widely accepted that cells adapt their mechanical properties to the stiffness of their surroundings. The link between cortical cell stiffness and substrate mechanics was hy...
Article
Full-text available
Two bipolar host materials 3‐CBPy and 4‐mCBPy are reported. These hosts are structural analogs of the common host materials CBP and mCBP wherein the phenyl rings have been replaced with pyridines. The two materials possess deep highest occupied molecular orbital (HOMO) and shallow lowest unoccupied molecular orbital (LUMO) levels along with suffici...
Article
Full-text available
Fluorescence imaging is an indispensable tool in biology, with applications ranging from single‐cell to whole‐animal studies and with live mapping of neuronal activity currently receiving particular attention. To enable fluorescence imaging at cellular scale in freely moving animals, miniaturized microscopes and lensless imagers are developed that...
Preprint
Full-text available
Dyslexia is a common neurodevelopmental disorder with a strong genetic component. Independent genetic association studies have implicated the KIAA0319 gene in dyslexia, however its function is still unknown. We developed a cellular knockout model for KIAA0319 in RPE1 cells via CRISPR-Cas9n to investigate its role in processes suggested but not conf...
Article
Low-threshold, room-temperature polariton lasing is crucial for future application of polaritonic devices. Conjugated polymers are attractive candidates for room-temperature polariton lasers, due to their high exciton binding energy, very high oscillator strength, easy fabrication, and tunability. However, to date, polariton lasing has only been re...
Article
A series of four 1,3,4-oxadiazole-based thermally activated delayed fluorescence (TADF) derivatives are reported as emitters for organic light emitting diodes (OLEDs). As a function of the nature of the substituent on the weak 1,3,4-oxadiazole acceptor their emission color could be tuned from green-blue to blue. The highly twisted conformation betw...
Article
Full-text available
Strong light-matter coupling can re-arrange the exciton energies in organic semiconductors. Here, we exploit strong coupling by embedding a fullerene-free organic solar cell (OSC) photo-active layer into an optical microcavity, leading to the formation of polariton peaks and a red-shift of the optical gap. At the same time, the open-circuit voltage...
Article
Full-text available
Advances in sensing technology raise the possibility of creating neural interfaces that can more effectively restore or repair neural function and reveal fundamental properties of neural information processing. To realize the potential of these bioelectronic devices, it is necessary to understand the capabilities of emerging technologies and identi...
Presentation
Mechanical forces exerted by cells are known to regulate many cellular functions, with cell invasion and metastasis being of particular importance in cancer. This study uses Elastic Resonator Interference Stress Microscopy (ERISM), a novel optical technique for force mapping, to measure – to our knowledge for the first time – the forces exerted by...
Preprint
Cardiac regeneration and stem cell therapies depend critically on the ability to locally resolve the contractile properties of heart tissue. Current regeneration approaches explore the growth of cardiac tissue in vitro and the injection of stem cell-derived cardiomyocytes (CMs) but scientists struggle with low engraftment rates and marginal mechani...
Article
Lead halide perovskites have attracted great attention due to their excellent optoelectronic properties, with great progress being made in their performance as light emitting diodes (LEDs), photodiodes, and solar cells. Demonstrating large scale, high-resolution patterning of perovskites is a key enabling step to unlock their full potential for a r...
Presentation
Cancer invasion and metastasis are complex processes, regulated by biochemical as well as physical cues. Understanding and quantifying the physical cues in a better way could lead to new therapeutic strategies against cancer invasion. This study uses Elastic Resonator Interference Stress Microscopy (ERISM), a novel optical technique for force mappi...
Presentation
The mechanical forces exerted by invadopodia have been measured using the Elastic Resonator Interference Stress Microscopy (ERISM) technique. Invadopodia are protrusions formed by cancer cell that enhance cancer invasion via degradation of extracellular matrix (ECM). The extreme stress sensitivity and the fast response of ERISM enabled us to measur...
Article
Full-text available
Optogenetics, photostimulation of neural tissues rendered sensitive to light, is widely used in neuroscience to modulate the electrical excitability of neurons. For effective optical excitation of neurons, light wavelength and power density must fit with the expression levels and biophysical properties of the genetically encoded light‐sensitive ion...
Article
Full-text available
Under adequate conditions, cavity polaritons form a macroscopic coherent quantum state, known as polariton condensate. Compared to Wannier-Mott excitons in inorganic semiconductors, the localized Frenkel excitons in organic emitter materials show weaker interaction with each other but stronger coupling to light, which recently enabled the first rea...
Conference Paper
We report the application of semiconductor nanodisk lasers within living cells. Our lasers have volumes 1000-fold smaller than eukaryotic nuclei, ultralow pulse energy lasing thresholds (Eth≈0.13pJ), and provide excellent spectral stability.
Conference Paper
Microscopic whispering gallery mode lasers detect minute changes in cellular refractive index inside individual cardiac cells and in live zebrafish. We show that these signals encode cardiac contractility that can be used for intravital sensing.