Welcome Grant - St. John's College
We received a Welcome Grant from St. John's College to created a setup for measuring linearly polarised light emission. This will be established in the device glovebox, alongside the LED testing rig, and will support our work on polarised light sources from perovskite nano platelet superlattices.
People involved: Dr. Junzhi Ye, Prof. Robert Hoye
John Fell Fund
We received a major project award from Oxford University's John Fell Fund to complete our device glovebox setup. With this, we will have a glovebox evaporator built-in, that has two inorganic and two organic sources, along with shielding to prevent cross-contamination. In addition, we will have an LED testing rig and PLQY setup built-in to the glovebox, allowing fresh devices to be tested inside an inert environment. This supports our work on light-emissive materials.
People involved: Dr. Junzhi Ye, Prof. Robert Hoye
Royce Industrial Collaboration Partnership Grant
2022 - 2023
This project was awarded through the Henry Royce Institute Industrial Collaboration Partnership scheme. Through this project, the group develops a new collaboration with Lightricity Ltd., an SME based in the Oxford Science Park. The focus of the project is to develop a testing box for standardised measurements of indoor photovoltaics that can be widely deployed and can push forward the development of novel technologies for indoor light harvesting. This ties in strongly with the priorities on indoor photovoltaics discussed in the Materials for Photovoltaic Systems roadmap made by the Henry Royce Institute, who Prof. Hoye co-led.
People involved: Dr. Huimin Zhu, Junzhi Ye, Dr. Dan Price, Ivy Liu, Hugh Lohan, Xiaoyu Guo, Prof. Robert Hoye
UKRI Frontier Grant (ERC Starting Grant)
2022 - 2027
This project was originally awarded through the ERC Starting Grant 2021 scheme, but is funded by UKRI
This project (HERALD) aims to instigate a step-change in how smart devices are powered by developing new classes of pnictogen-based semiconductors to more efficiently collect the widely-available energy from lighting inside buildings. Such energy can be renewably harvested with indoor photovoltaics (IPVs), which is highly appealing for powering the billions of autonomous smart devices driving the fourth industrial revolution. However, industry-standard IPVs (hydrogenated amorphous silicon; a-Si:H) have efficiencies up to only ~20%, with most commercial devices <10% efficient.
HERALD will develop IPVs from novel classes of rudorffites and chalcohalides, which have potential to reach >48% efficiency under indoor lighting. These are low-toxicity, high-stability materials based on the pnictogens bismuth and antimony, and their considerable potential for indoor light harvesting is just starting to emerge. HERALD will transform these novel compounds into leading IPVs using a hierarchical characterisation approach, from the macro- to near-atomic-scale. Along the way, fundamental understanding will be gained to learn what the performance-limiting factors are and how they can be systematically mitigated. The endpoint will be high-performing, durable test devices with low environmental impact. The materials will be rapidly grown at scale using a novel plasma-spray technique, and the IPVs prototyped in commercial smart devices.
In addition to enabling a more sustainable ecosystem of smart devices, the new fundamental insights into rudorffites and chalcohalides will open up the possibility for numerous applications beyond IPVs, from clean solar fuel production to radiation detection for medical imaging.
People involved: Dr. Huimin Zhu, Ivy Liu, Hugh Lohan, Xiaoyu Guo Prof. Robert Hoye
2021 - 2024
This project (ABZ2-PV) aims to develop a new class of ternary chalcogenide semiconductors for photovoltaics (PVs) that can achieve efficient performance when made cost-effectively. In the ABZ2 family of compounds, A is a monovalent cation, B a trivalent pnictogen cation, and Z a divalent anion. There is significant structural and chemical versatility in this family of compounds. The materials will be developed based on two core conceptual focuses: i) defect tolerance, and ii) carrier-phonon interactions. Defect tolerance allows low non-radiative recombination rates to be achieved despite high defect densities. Carrier-phonon interactions significantly influence charge-carrier transport in these materials, and have recently been found to be a limiting factor in many halide-based materials. By studying a specific set of compounds, and using an interlink experimental-computational approach, this project seeks to gain insights into how materials with high defect tolerance and low carrier-phonon interaction strength can be found. These insights will be used to identify the most promising set of materials to develop further into devices.
People involved: Yi-Teng Huang, Yuchen Fu, Prof. Robert Hoye
2018 - 2023
This project focuses on developing novel metal-halide semiconductors for next-generation optoelectronics. Through this research programme, we have developed new approaches for growing oxide buffer layers on thermally-sensitive active-layer materials, which has led to efficient semitransparent devices for tandem photovoltaics between cost-effective halide perovskites and industry-standard silicon photovoltaics (e.g., see paper in ACS Energy Letters). This approach and device structure can be broadly applied, and we are also working on extending our approach to growing oxides to applications beyond buffer layers and toward transparent electrodes. Through this programme, we have also developed lead-free alternatives to halide perovskites, focusing on compounds based on structural and chemical analogy, including Cs2AgBiBr6 and BiOI. Our work has spanned from fundamental studies into these materials (e.g., see paper in Advanced Functional Materials) through to device applications. An important opportunity that arose from this work is the opportunity to apply these materials in devices beyond photovoltaics, such as photoelectrochemical cells (see paper in Nature Materials) and radiation detectors (patent recently filed).
People involved: Prof. Robert Hoye, Jason Ye, Kavya Reddy Dudipala
2021 - 2023
The current COVID-19 pandemic has laid bare our severe vulnerability to pandemics, and the critical importance of vaccines to counter these associated society and economic effects. A critical challenge with the equitable deployment of vaccines is the limited thermal stability, particularly vaccines based on RNA. This project aims to stabilise RNA-based vaccines in ambient conditions, thus eliminating the need for cold-chains, through a combination of encapsulating nanoparticles and nonporous storage for the nanoparticles. This project draws off the expertise of colleagues in Chemical Engineering at Imperial (Rongjun Chen and Jerry Heng) in vaccine nano formulation development and surface-particle interactions, and nanopatterning (Peter Petrov), as well us in surface functionalisation through the growth of conformal oxide films.
People involved: Dr. Dan Price, and (external) Dr. Apanpreet Kaur, Shuning Xiang, Dr. Peter Petrov, Prof. Jerry Heng, Dr. Rongjun Chen, Prof. Robert Hoye