Congratulations to Yan Wang and Erica Chen on DPhil Thesis Submission

The Group is delighted to congratulate Yan Wang and Jingyan (Erica) Chen on successfully submitting their DPhil theses in Trinity Term 2026 at the University of Oxford, completing the final academic requirement for the award of the Doctor of Philosophy.
Their submissions represent the culmination of several years of innovative research in advanced photovoltaic materials and device engineering, and mark another important milestone for the Electronic and Interface Materials Laboratory.

Jingyan (Erica) Chen
Supervised by Professor Ruy Sebastian Bonilla and Dr Matthew Wright, Erica's thesis, "Charged Oxide Inversion Layers for Emitter Formation in Silicon Solar Cells," explores a fundamentally new approach to forming silicon solar cell emitters using embedded dielectric charge rather than conventional high-temperature doping. Her research established a complete pathway from controlled potassium-ion charge embedding in silicon dioxide through to the fabrication of fully functional charged oxide inversion layer (COIL) solar cells.
Among her achievements, Erica demonstrated the highest reported interface charge densities for Si/SiO₂ interfaces, developed inversion-layer emitters with record-low sheet resistance, and successfully integrated the COIL concept with laser-doped selective emitters to fabricate complete solar cells entirely in-house. Her work establishes dielectric charge engineering as a promising alternative route for future silicon photovoltaics and semiconductor devices.

Yan Wang
Supervised by Professor Ruy Sebastian Bonilla, Yan's thesis, "Understanding and Engineering Zinc Oxide Nanolayer Contacts for Silicon-based Tandem Photovoltaics," addresses one of the key challenges facing tandem solar cells: developing sustainable, indium-free transparent conducting contacts.
Her work established aluminium-doped zinc oxide (AZO) nanolayer stacks as multifunctional transparent passivating contacts for silicon, combining detailed interface characterisation with device engineering. Through advanced techniques including synchrotron X-ray photoelectron spectroscopy, neutron reflectometry, Kelvin probe surface photovoltage, and time-of-flight secondary ion mass spectrometry, Yan developed a comprehensive understanding of the chemical and electronic mechanisms governing silicon passivation. Her research demonstrated record-low recombination currents for AZO-based contacts and provides a scalable pathway towards high-efficiency, indium-free tandem photovoltaics.

Looking Ahead
Erica and Yan have each made significant contributions to the group's research portfolio through numerous publications, international collaborations, and the development of new experimental methods. Their work has advanced our understanding of semiconductor interfaces, dielectric engineering, transparent conducting contacts, and next-generation photovoltaic technologies.
Although thesis submission marks the completion of the final academic requirement for the DPhil, it also marks the beginning of exciting new chapters in their research careers.
The entire group congratulates Erica and Yan on this outstanding achievement and wishes them every success in the next stages of their scientific journeys.