Mohammed Reza Kokaba

Topic

Upscaling Flexible Perovskite Solar Cells and Modules Made in Ambient Air

Department of Electrical and Computer Engineering

Date & location

• Thursday, October 29, 2026

• 1:00 P.M.

• Elliott Building, Room 305

Reviewers

Supervisory Committee

• Dr. Makhsud Saidaminov, Department of Electrical and Computer Engineering, UVic (Supervisor)

• Dr. Tao Lu, Department of Electrical and Computer Engineering, UVic (Member)

• Dr. Sravya Tekumalla, Department of Mechanical Engineering, UVic (Outside Member) 

External Examiner

• Dr. Niloofar Akbarian-Saravi, Department of Decision Sciences, MacEwan University 

Chair of Oral Examination

• Dr. Nikki Macdonald, School of Public Administration, UVic

   

Abstract

Photovoltaic (PV) technologies are essential for meeting the growing demand for sustainable and low carbon energy, with silicon-based PV currently serving as the dominant technology because of their high efficiency, stability, and mature manufacturing infrastructure. However, the rigid form factor and energy-intensive processing associated with conventional silicon PV can limit their suitability for emerging applications requiring lightweight and flexible devices. Perovskite PV have therefore attracted significant attention as a promising alternative because of their high power-conversion efficiency (PCE), low-temperature processability, and compatibility with flexible and scalable manufacturing. However, translating their laboratory scale performance into practical flexible solar cells and modules presents several interconnected challenges, including the formation of uniform functional layers on flexible substrates, reproducible perovskite crystallization under ambient conditions, large-area module fabrication, and the development of environmentally compatible processing routes. This thesis attempts to address these challenges through the development of scalable fabrication strategies for flexible perovskite solar cells and modules, with particular emphasis on electron transport layer engineering, ambient-air perovskite processing, and environmentally compatible device fabrication.

First, the electron transport layer (ETL) was engineered to improve the performance of flexible perovskite solar cells fabricated on polyethylene terephthalate/indium tin oxide (PET/ITO) substrates. Modification of commercial tin oxide (SnO2) nanoparticle dispersions using phenyltrimethylammonium chloride enhanced particle-to-particle interactions, resulting in improved film coverage and morphology. The modified SnO2 layer also influenced the subsequent nucleation and crystallization of the perovskite absorber, demonstrating the importance of considering the electron transport layer as an active component of perovskite film formation.

Second, the sensitivity of perovskite crystallization to ambient humidity was investigated using a compositionally graded approach. By systematically varying the concentrations of methylammonium chloride and propylammonium chloride, the interaction between additive chemistry, water, and relative humidity was established. An optimized formulation promoted robust desired phase of formamidinium lead iodide α-FAPbI3 formation over a broad range of humidity conditions by moderating moisture induced degradation and promoting defect suppressed crystallization. This approach enabled humidity-tolerant fabrication of scalable perovskite solar cells and monolithic modules, demonstrating the potential of precursor-chemistry engineering to reduce the sensitivity of perovskite fabrication to environmental fluctuations.

Finally, an environmentally compatible fabrication strategy was developed for flexible perovskite PV. A water-based chemical bath deposition process was investigated for SnO2 formation on PET/ITO substrates. Direct chemical bath deposition (CBD) produced insufficient coverage; however, introducing a thin SnO2 nanoparticle seeding layer promoted heterogeneous nucleation and subsequent SnO2 growth, substantially improving electron transport layer formation. The optimized nanoparticle/chemical-bath-deposited SnO2 architecture enabled high performance flexible perovskite solar cells and was further extended to all-green flexible perovskite modules fabricated under ambient air conditions. The improved module performance demonstrated the importance of continuous and conformal electron transport layer coverage for large-area flexible devices. In addition to device fabrication, module-level processing was investigated through the optimization of laser-scribing conditions and the development of an outdoor tracking platform for evaluating PV operation under naturally varying conditions. Overall, this thesis establishes a progression from functional layer and interface engineering to humidity-tolerant perovskite crystallization and environmentally compatible flexible module fabrication. The results provide practical strategies toward scalable, flexible, and ambient-air perovskite PV while identifying remaining challenges related to interfacial losses, large-area uniformity, and module performance. Figure A summarizes the three main research directions investigated throughout this thesis, illustrating the progression from flexible device and ETL engineering to humidity-tolerant perovskite processing and environmentally compatible flexible PV module fabrication.