Advancing Antimony Selenide Photovoltaics: Novel Strategies for Material Processing and Interface Engineering

Abstract

The urgent need for sustainable photovoltaic (PV) technologies motivates the study of Sb2Se3, a material with earth-abundance, intrinsic stability, and favourable optoelectronic properties. Yet its power conversion efficiency (PCE) remains far below the theoretical limit due to a large open-circuit voltage deficit, likely caused by absorber defects, orientation control, and interfacial recombination. Thermal processing dominates the energy and time budgets of thin-film PV fabrication, limiting throughput and scalability. Overcoming these challenges requires rapid, low-thermal-budget processes compatible with high-throughput manufacturing.
This thesis demonstrates the first systematic application of photonic curing (PC), a non-equilibrium annealing strategy, to Sb2Se3 thin-film solar cells with a glass/FTO/TiO2/Sb2Se3/P3HT/Au architecture. The work began with optimisation of rapid thermal evaporation parameters to produce reproducible Sb2Se3 films with columnar morphology and preferential (211)/(221) orientation. Under these conditions, a champion device achieved a PCE of 6.8%. PC was then applied at multiple fabrication stages to evaluate its impact on different layers. For solution-processed TiO2 electron transport layers on glass/FTO, PC enabled anatase crystallisation without the need for metal grids or dopants. Annealing times in this study were comparable to thermal annealing due to instrument limitations, and PC still reduced energy consumption and achieved PCEs of 3.7%. PC also enabled the crystallisation of amorphous Sb2Se3 absorbers, while preserving stoichiometry, suppressing secondary phases, and promoting favourable orientations with larger grains. Micro-pulse curing achieved device efficiencies comparable to vacuum thermally annealed samples, demonstrating strong potential for rapid, low-thermal-budget processing. Finally, PC post-treatment of crystalline Sb2Se3 absorbers enhanced crystallinity, reduced surface roughness, and improved back-contact quality. This increased champion device PCEs from 5.1% to 8.2%, with concurrent improvement in open-circuit voltage and fill factor.
Collectively, this work establishes PC as a versatile and energy-efficient processing route for Sb2Se3 solar cells, demonstrating a scalable and transferable methodology for roll-to-roll compatible fabrication of emerging thin-film PV technologies.

Date of Award	27 Nov 2025
Original language	English
Awarding Institution	Northumbria University
Supervisor	Oliver Hutter (Supervisor) & Vincent Barrioz (Supervisor)