Gregory Burwell

• PhD, MMathPhys
• Senior Lecturer at Swansea University

Transparent conducting electrodes (TCEs) are integral components in optoelectronic devices, facilitating both light transmission and electrical conduction. Over the past four decades, substantial advancements have been made in TCE materials, including transparent conducting oxides (TCOs) such as indium tin oxide (ITO) and fluorine‐doped tin oxide (...

As the world strives toward its net‐zero targets, innovative solutions are required to reduce carbon emissions across all industrial sectors. One approach that can reduce emissions from food production is agrivoltaics—photovoltaic devices that enable the dual‐use of land for both agricultural and electrical power‐generating purposes. Optimizing agr...

Organic–inorganic halide perovskite semiconductors have revolutionized next-generation photovoltaics (PV) due to several characteristics such as solution-processability, gap tunability, and excellent charge generation and transport properties. This has made them very adaptable for various applications in light harvesting and photodetection. One suc...

As the Internet of Things (IoT) expands, the need for energy-efficient, self-powered devices increases. This study examines light power resource availability for photovoltaics (PV) in various environments and its potential in self-powered IoT applications. We analyse light sources, considering spectral distribution, intensity, and temporal variatio...

Indoor photovoltaic (IPV) devices are poised to make a significant contribution to the proliferation of the “Internet of Things” (IoT). For the accurate intercomparison of IPVs (and, hence, to advance the rational development of the technology), lighting conditions representative of those in typical indoor settings must be created reproducibly. As...

Due to their tailorable optical properties, organic semiconductors show considerable promise for use in indoor photovoltaics (IPVs), which present a sustainable route for powering ubiquitous “Internet-of-Things” devices in the coming decades. However, owing to their excitonic and energetically disordered nature, organic semiconductors generally dis...

We report the effect of electron-beam patterning on the water uptake and ionic conductivity of Nafion films using a combination of x-ray photoelectron spectroscopy, quartz crystal microbalance studies, neutron reflectometry, and AC impedance spectroscopy. The aim was to more fully characterize the nature of the nanoscale patterned Nafion structures...

Abstract The effect of electron‐beam patterning on the water uptake and ionic conductivity of Nafion films using a combination of X‐ray photoelectron spectroscopy, quartz crystal microbalance studies, neutron reflectometry, and impedance spectroscopy is reported. The aim is to further characterize the nanoscale patterned Nafion structures recently...

High‐quality, alumina thin films are extensively used as dielectrics, passivation layers, and barrier layers in electronics and many other applications. However, to achieve optimum stoichiometry and thus performance, the layers are often grown at elevated temperatures (>200 °C) using techniques such as atomic layer deposition (ALD). This is problem...

Due to their tailorable optical properties, organic semiconductors show considerable promise for use in indoor photovoltaics (IPVs), which present a sustainable route for powering ubiquitous "Internet-of-Things" devices in the coming decades. However, owing to their excitonic and energetically disordered nature, organic semiconductors generally dis...

Poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been one of the most established hole transport layers (HTL) in organic solar cells (OSCs) for several decades. However, the presence of PSS⁻ ions is known to deteriorate device performance via a number of mechanisms including diffusion to the HTL‐active layer interface and unwa...

The world’s energy consumption is expected to grow vastly over the next few decades. Contributing to this growing energy demand is the advent of the Internet-of-Things (IoT), through which many devices and sensors may one day share immense quantities of information to benefit society as a whole.[1] Indoor photovoltaics (IPVs) based on easy-to-proce...

Organic semiconductor‐based photovoltaic (OPV) devices have many properties that make them attractive for indoor applications, such as tailorable light absorption, low embodied energy manufacturing and cost, structural conformality, and low material toxicity. Compared to their use as organic solar cells (OSCs) for standard outdoor solar harvesting,...

Infectious disease outbreaks remain an ever‐prevalent global issue. The associated demand for rapid diagnostics and onsite testing will play an increasing and critical role in disease surveillance, prevention of the spread of infection, as well as timely commencement of treatment. Reported here is a graphene–gold nanoparticle hybrid sensor platform...

Graphene-based point-of-care (PoC) and chemical sensors can be fabricated using photolithographic processes at wafer-scale. However, these approaches are known to leave polymer residues on the graphene surface, which are difficult to remove completely. In addition, graphene growth and transfer processes can introduce defects into the graphene layer...

Melanins are an essential natural pigment found throughout nature. Due to their inherent biocompatibility, optical and electronic properties, the melanins are attracting attention as model materials for sustainable organic optoelectronic and bioelectronic applications. Standard melanin is notoriously insoluble, which complicates processability cons...

Intense research interest in organic photovoltaic (OPV) devices has resulted in steadily improving figures of merit in recent years. Typically, these devices are fabricated by processing active and buffer layers on transparent conductive electrodes (TCEs). Superlative OPV devices are small (<≈0.1 cm2). The sheet resistance of available monolithic t...

Transparent conducting electrodes (TCEs) are key components of optoelectronic devices where input or output light coupling are central functions—for example, solar cells, light‐emitting diodes, or displays. Indium tin oxide (ITO) has been the TCE of choice for over three decades, and there are few alternatives. The characteristic size of devices ma...

Affinity biosensors based on graphene field-effect transistor (GFET) or resistor designs require the utilization of graphene’s exceptional electrical properties. Therefore, it is critical when designing these sensors, that the electrical properties of graphene are maintained throughout the functionalization process. To that end, non-covalent functi...

A hybrid biosensor based on a graphene resistor functionalized with self-assembled Graphene-AuNPs (Gold Nanoparticles) is demonstrated for the real-time detection of hepatitis B surface antigen (HBsAg). The hybrid biosensor consists of a ssDNA sequence attached to a graphene resistor device via π-π stacking interactions in combination with a ssDNA...

Integrated circuits based on CMOS (complementary metal-oxide semiconductors) are at the heart of the technological revolution of the past 40 years, as these have enabled compact and low cost micro-electronic circuits and imaging systems. However, the diversification of this platform into applications other than microcircuits and visible light camer...

Integrated circuits based on CMOS (complementary metal-oxide semiconductors) are at the heart of the technological revolution of the past 40 years, as these have enabled compact and low cost micro-electronic circuits and imaging systems. However, the diversification of this platform into applications other than microcircuits and visible light camer...

Graphene is currently being investigated for use in a wide range of applications, and it is therefore necessary to be able to pattern the material efficiently and consistently. Although graphene may be patterned using standard lithographic methods, certain care needs to be taken when handling the 2D material. For example, photoresist layers coated...

Graphene is currently being investigated for use in a wide range of applications, and the capability of patterning the material efficiently and consistently is therefore a necessity. Although graphene may be patterned using standard lithographic methods, care needs to be taken when processing the 2D material with certain polymer resists. For exampl...

Graphene is a two-dimensional crystalline form of carbon that has attracted intensive focus from various research disciplines since the publication of a seminal paper in 2004 by Novoselov, Geim et al. Of particular interest is the use of graphene in sensors. By chemically modifying, or functionalizing, graphene, it is possible to modify the its sur...

Residues on graphene substrates from polymer-supported transfer and lithography can significantly degrade device performance. Using Fourier transform infrared (FTIR), Raman spectroscopy and Auger electron spectroscopy (AES), cellulose acetate butyrate (CAB) dissolved in ethyl acetate is shown to leave minimal polymer residue on graphene after subst...

Electrochemical immunosensor devices comprise of an antibody immobilised onto a semiconducting or conducting substrate. The use of epitaxial graphene in immunosensors allows for the detection of an antigen specifically bound to the immobilised antibody by monitoring the current modulation of lithographically fabricated graphene channel devices. Mul...

A generic electrochemical method of 'bioreceptor' antibody attachment to phenyl amine functionalized graphitic surfaces is demonstrated. Micro-channels of chemically modified multi-layer epitaxial graphene (MLEG) have been used to provide a repeatable and reliable response to nano-molar (nM) concentrations of the cancer risk (oxidative stress) biom...

By combining ozone and water, the effect of exposing epitaxial graphene on silicon carbide to an aggressive wet-chemical process has been evaluated after high temperature annealing in ultra high vacuum. The decomposition of ozone in water produces a number of oxidizing species, however, despite long exposure times to the aqueous-ozone environment,...

Photochemistry plays a critical role in modern semiconductor electronics, primarily through the use of photoactive polymers or photoresists in the lithographic processes used to fabricate semiconductor devices. Photoactive polymers have been extensively researched in order to develop resists that are chemically robust and that are able to produce s...

Human chorionic gonadotropin (hCG), a 37 kDa glycoprotein hormone, is a key diagnostic marker of pregnancy and has been cited as an important biomarker in relation to cancerous tumors found in the prostate, ovaries and bladder. A novel chemically-modified epitaxial graphene diagnostic sensor has been developed for ultrasensitive detection of the b...

Biosensor diagnostics based on bio-functionalized semiconductor devices are an important development in ultrasensitive sensors for early detection of disease biomarkers. Electrochemical devices using chemically modified graphene (CMG) channels are excellent candidates for nano-biosensors. This paper presents the development of novel antibody functi...