• Energy Research
• OA Publications Mandate: No close
• 2020 close

I aim to demonstrate light weight, flexible solar cells with high efficiency to cost ratio using compound semiconductors for niche applications like wearable electronics and un-manned, light weight drones. High power conversion efficiency in solar cells can be achieved by controlling the (i) light absorption and emission characteristics of the absorber and (ii) separation of photo-generated electron-hole pairs, to generate current. Nanotechnology has emerged as a powerful tool to control the light-semiconductor interaction and nanostructured semiconductors with absorption and emission characteristics suitable for high efficiency solar cells have already been demonstrated. Nanostructured semiconductors also reduce the volume of semiconductor material required for high efficiency solar cells, providing a pathway to light weight and flexible devices. Charge separation and extraction from these nanostructured semiconductors is currently limiting the efficiency of nanostructured solar cells. Conventionally, a p-n junction is used to separate photo-generated electrons and holes in a solar cell. It is, however, very challenging to form good quality p-n junctions in nanostructures. In this project, I propose a novel mechanism for charge extraction from nanostructures that eliminates the need to form p-n junctions, to achieve the high power conversion efficiencies promised by nanostructured solar cells. This project will benefit research communities worldwide interested in nanostructured photovoltaics or the third-generation photovoltaic technologies and is the first step towards establishing a new research programme on nanostructured compound semiconductor photovoltaics in the UK. In addition to uncovering fundamental physics at the nanoscale, this project paves the way towards sustainable and green energy generation by addressing the important issue of efficiency to cost ratio of photovoltaics. The technology developed during this project will generate intellectual property related to nanostructured PV. I will work with Cardiff University's commercial development team and Cardiff University's patent holding company, University College Cardiff Consultants Limited (UC3) to protect any IP resulting from this project. I will work with the recently established Institute for Compound Semiconductors (ICS) and Innovate UK's Advanced Materials, High Value Manufacturing and Compound Semiconductor Catapult (CSC) programmes to transfer the research outcomes to industry, creating technological jobs in the energy sector in the UK.

The primary aim of the project is to quantify the influence of small-scale hydropower facilities on the movement and survival of freshwater fish of high economic and conservation concern. A secondary aim is to develop recommendations for potential mitigation options to protect fish at small-scale hydropower sites should negative effects be identified. Telemetry techniques will be used in the field to quantify the probability of passage through the turbines and associated injury rates and mortality of adult and juvenile life-stages using a combination of telemetry techniques. Second order effects, including delay and avoidance behaviour exhibited in response to acoustic and hydrodynamic conditions encountered at the hydropower facilities, will be assessed. Fine-scale controlled experiments will be conducted to further quantify fish response to acoustic and hydrodynamic conditions replicated.

This project fits squarely within the EPSRC's Energy theme (Solar Technologies and Materials for Energy Applications) and is overlapping with the Physical Science and manufacturing the future themes. This project will focus on the development of transparent electrodes based on nano-structured ultra-thin metal films, matched to the needs of the emerging generation of organic and perovskite photovoltaics. The project will focus particularly on chemical approaches to stabilizing these electrodes towards oxidation in air and the development of new chemical approaches to achieving large area patterning of these electrodes. The project will span electrode fabrication and characterisation (including optical modelling), as well as photovoltaic device fabrication and characterisation, and so represents a truly inter-disciplinary research training opportunity.

The photovoltaics field has been revolutionized by the emergence of lead-based hybrid perovskites. These materials are high quality semiconductors that can be deposited cheaply, from solution, at room temperature. However, the toxicity of lead and stability issues for these perovskites are driving a new search for more benign and stable alternatives. In this project we will try to find other chemically processable Bi based compounds which resemble the same defect tolerance as Lead based perovskites, but tackling the two major drawbacks mentioned earlier. The project will study the effect of systematic doping of BiOI with chalcogenides S and Se on the optical and electronic properties of the films. The aim is to form idealized microstructures in large area, chemically grown thin films and in doing so optimize the physical properties and optimize transport properties to give long diffusion lengths. Different experiments will be conducted and will give insight into routes to improve the transport properties and minority-carrier lifetimes in BiOI and related films, and to maximize charge extraction at device interfaces, all of which should provide a route to more efficient photovoltaic devices.

The generation of energy is the most important scientific and technological challenge that faces humankind in the 21st century. In order to supply the demand of increasing global energy requirements, the development of low cost, easily processable, efficient photovoltaics (PV) is essential. Third generation PV offers a potentially low cost, easily processable and efficient technology and before us lays a great opportunity in solar energy research. International progress in PV research and technology is currently running at an unparalleled rate, with major contributions from the SPECIFIC and Ser Solar groups. The extremely rapid evolution of solution processed halide perovskite-based solar cells during the last few years (reaching efficiencies in the range of 15-20%, including certified 20.1%) makes them an extremely strong candidate to develop a cost and performance competitive PV technology. Photovoltaic devices which utilise light harvesting perovskite chemistries could potentially offer a cheaper and simpler technology in comparison to the typically favoured silicon solar cell. However, current issues when using perovskites for PV application include physicochemical degradation, instability and lifetime issues up on exposure to ambient conditions. The fundamental workings and reasoning for the aforementioned problems when using perovskite absorbers are yet to be fully understood. The project is concerned with gaining a better understanding of halide perovskite chemistry through identification and investigation of the manufacturing conditions or parameters which may lead to device instabilities. Fluorescence microscopy and fluorescence spectroscopy are two techniques which will be applied to investigate the photoluminescent properties and morphologies of a range of perovskite materials prepared under different conditions. The project research will explore routes to increasing the efficiency and light harvesting ability of these devices. There is also scope to use X-ray diffraction to investigate the crystalline structure of the perovskite layer and to determine whether the uniformity of this layer (amongst other layers) is affected by the alteration of certain parameters during device manufacture. The degradation of perovskite is believed to be exacerbated due to reaction with oxygen which will be investigated using transient absorption spectroscopy as a method to monitor oxygen diffusion within halide-perovskite solar cells. The overall aim is to develop an understanding of device photophysics and photochemistry resulting in the development of new materials to improve stability and cost and leading to world leading, high impact articles in the premier international journals in the field.

Production of a prototype internal blade inspection system for use inside Offshore Wind Turbine blades including a cost benefit analysis.