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Engineering nanomaterials for efficient LEDs

PGR-P-1460

Key facts

Type of research degree
PhD
Application deadline
Tuesday 31 January 2023
Project start date
Sunday 1 October 2023
Country eligibility
International (open to all nationalities, including the UK)
Funding
Competition funded
Source of funding
University of Leeds
Supervisors
Dr Marco Califano and Dr Kevin Critchley
Schools
School of Electronic and Electrical Engineering, School of Physics and Astronomy
<h2 class="heading hide-accessible">Summary</h2>

A fully-funded 3.5 year PhD Studentship is available to work on an exciting interdisciplinary materials science project on the design, synthesis and optimisation of colloidal quantum dot-based blue LEDs, combining state-of-the-art computational modelling approaches with chemical synthesis and materials characterisation techniques. Semiconductor colloidal Quantum Dots (cQDs) exhibit unique size-dependent electronic and optical properties which make them ideally suited for a wide range of applications. In particular, InP has emerged as a promising environmentally friendly material, that at the nanoscale exhibits a size-tunable emission in the visible region of the spectrum. Applications of InP cQDs range from optoelectronics to photovoltaics, and from bio-imaging to memory storage and lighting. Historically, InP-based cQD-LEDs have exhibited low efficiency, due to the low photoluminescence (PL) quantum yield (QY) which results from decreased radiative recombination rates. Recently this has changed, with examples of near 100% PL QY reported for InP/ZnSe/ZnS cQDs. The record PL QY was attributed to an improved surface passivation achieved by means of the multilayer shell structure. The growth of multiple shells introduces additional levels of complexity to the synthesis of the cQDs, resulting in a more time-consuming and costly manufacture of the final devices. Yet, their role in the PL QY increase remains poorly understood. <br /> Our group recently showed that even in the absence of surface traps the radiative recombination times in InP cQDs can be very long (tens of microseconds), and the associated PL weak, with a low QY, depending on the surface composition of the cQD. It follows that the effect of the presence of multiple shells is not the assumed improved surface passivation that removes surface defects. In this project, that combines chemistry, experimental physics and computational materials science, you will investigate the real origin of the huge QY enhancement observed in core/multi-shell structures and apply this knowledge to design much simpler structures (ideally without any shell) that exhibit high QY and strong PL, for application in cQD-LEDs. You will then perform accurate modelling of the cQD-LED devices, aimed at optimising their performance by screening various parameters before their actual experimental implementation. Your experimental results will then feed back into your modelling. You will use a multiscale theoretical/experimental approach that combines ab-initio modelling at the atomistic scale, dot array modelling at the mesoscale and device design and simulation at a larger scale, with chemical synthesis, experimental single-dot measurements of elemental composition, optical characterisation, device manufacturing and characterisation.

<h2 class="heading hide-accessible">Full description</h2>

<p>You can start your PhD from 1 August 2023 but you must be able to start by no later than 1 November 2023.</p> <p>Important dates:</p> <ul> <li style="text-align: justify; margin-left: 8px;">Application deadline: 31 Jan 2023</li> <li>Interview of shortlisted candidates: Feb 2023</li> <li>Scholarship offer letter: March/April 2023</li> </ul>

<h2 class="heading">How to apply</h2>

<p>Formal applications for a research PhD degree should be made online through the&nbsp;<a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University&#39;s website</a>. Please state clearly in the Planned Course of Study section that you are applying for <em><strong>PHD Electronic &amp; Electrical Engineering FT</strong></em> and in the research information section&nbsp;that the research project you wish to be considered for is <strong><em>Engineering nanomaterials for efficient LEDs</em></strong> as well as&nbsp;<a href="https://eps.leeds.ac.uk/electronic-engineering/staff/194/dr-marco-califano">Dr Marco Califano</a> as your proposed supervisor.</p> <p>If English is not your first language, you must provide evidence that you meet the University&#39;s minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p> <p class="MsoNoSpacing">Applications will be considered on an ongoing basis. &nbsp;Potential applicants are strongly encouraged to contact the supervisors for an informal discussion before making a formal application. &nbsp;We also advise that you apply at the earliest opportunity as the application and selection process may close early, should we receive a sufficient number of applications or that a suitable candidate is appointed.</p> <p>Please note that you must provide the following documents in support of your application by the closing date of 31 January 2023:</p> <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> <li>Funding information including any alternative sources of funding that you are applying for or if you are able to pay your own fees and maintenance</li> </ul>

<h2 class="heading heading--sm">Entry requirements</h2>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

<h2 class="heading heading--sm">English language requirements</h2>

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.

<h2 class="heading">Funding on offer</h2>

<p class="MsoNoSpacing">A highly competitive School of Electronic &amp; Electrical Engineering Studentship consisting of the award of fees at the UK fee rate of &pound;4,596 or Non-UK fee rate of &pound;25,500 (currently in academic session 2022/23) together with a maintenance grant (currently &pound;17,668 for session 2022/23) for 3.5 years.</p> <p>This opportunity is open to all applicants. All candidates will be placed into the School of Electronic &amp; Electrical Engineering Studentship Competition and selection is based on academic merit.<br /> <br /> <strong>Important:&nbsp;</strong> Any costs associated with your arrival at the University of Leeds to start your PhD including flights, immigration health surcharge/medical insurance and Visa costs are <strong>not</strong> covered under this studentship.</p> <p>Please refer to the&nbsp;<a href="https://www.ukcisa.org.uk/">UKCISA</a>&nbsp;website for&nbsp;information regarding Fee Status for Non-UK Nationals.</p>

<h2 class="heading">Contact details</h2>

<p>For further information about this project, please contact Dr Marco Califano: e: <a href="mailto:m.califano@leeds.ac.uk">m.califano@leeds.ac.uk</a> or Dr Kevin Critchley: e: <a href="mailto:k.critchley@leeds.ac.uk">k.critchley@leeds.ac.uk</a></p> <p>For further information about your application, please contact Doctoral College Admissions: e:&nbsp;<a href="mailto:phd@engineering.leeds.ac.uk">phd@engineering.leeds.ac.uk</a></p>


<h3 class="heading heading--sm">Linked funding opportunities</h3>
<h3 class="heading heading--sm">Linked research areas</h3>