Jiselle Ye

Jiselle Ye is a Ph.D. candidate in the Materials Science program at the Colorado School of Mines, conducting research on defect characterization of perovskite solar cells under the joint supervision of Dr. Kai Zhu and Dr. Joe Berry at the National Renewable Energy Laboratory (NREL) and Dr. Eric Toberer at Mines. Her work centers around elucidating the role of Pb-N and Sn-N chemical species in defect formation and passivation mechanisms, with the goal of improving the efficiency, stability, and commercial viability of perovskite photovoltaic technologies. By employing advanced spectroscopic and microscopic characterization techniques, Jiselle systematically correlates molecular-scale defects with film quality and macroscopic device performance, offering actionable insights for materials optimization.  

Being able to collaborate with scientists from world-class facilities and contribute to cross-disciplinary efforts aimed at overcoming critical bottlenecks in perovskite solar cell development has been the best part of her research career. Her approach aims to combine fundamental materials science with applied process engineering, yielding frameworks for scalable defect control that inform both academic and industrial innovation.  

Looking ahead, Jiselle aspires to continue pioneering research in renewable energy materials while supporting the next generation of scientists. Whether through academic mentorship or industry leadership, she is committed to fostering scientific curiosity and equipping future researchers with the tools to tackle global energy challenges.

Graduate Advisor: Joe Berry, Kai Zhu (NREL); Eric Toberer (Colorado School of Mines)
IRES-Perovskites Host: Steve Albrecht (Helmholtz Zentrum Berlin)

Effects of Precursor Solution Order of Mixing on Tin-Lead Perovskite Solar Cells
Tin–lead (Sn–Pb) mixed perovskites are promising candidates for tandem photovoltaics due to their tunable bandgaps and growing device efficiencies. However, the reproducibility and stability of these materials remain critical challenges, often influenced by subtle processing variables. In this work, we investigate how the order of precursor mixing in the perovskite solution affects the chemical environment, film formation, and device performance. We found that the sequence of reagent addition alters solution species. Using a Sn–Pb system, we compared different mixing orders and found that films prepared with the ideal sequence exhibited reduced unreacted PbI₂, higher photoluminescence quantum yield, and improved light stability. Corresponding devices showed improved power conversion efficiency, open-circuit voltage, short-circuit current density, and fill factor, along with enhanced thermal stability. These results underscore the importance of early-stage solution chemistry and demonstrate that the mixing order can influence the crystallization pathway, defect passivation, and long-term device performance in Sn–Pb perovskite solar cells.