Pressure engineering of photovoltaic perovskites - Dr. Gang Liu

MARCH 13, 2019

A new comprehensive study led by Dr. Gang Liu, a staff scientist at HPSTAR, reviewed the manipulation, modification, and improvement of photovoltaic perovskite materials by pressure engineering. The study focuses on the unique overlapping region between Green energy, materials, and engineering and explores whether desirable characteristics for next-generation materials-by-design are obtainable with pressure. It was recently published in MATERIALS TODAY.

The study addresses the critical need to review and understand the fundamental material properties of perovskite absorbers, including traditional bulk 3D perovskites and novel 2D/0D/double perovskites under pressure conditions, and explores the possibility of pressure/strain engineering to modify energy materials for photovoltaic applications in the core region of the “Three Greens” (Fig.1).

Dr. Liu’s research explores diverse phenomena and the origins of the pressure-induced structural evolution in various photovoltaic perovskites, including traditional 3D bulk perovskites, 2D layered perovskites, 0D quantum dots, and double perovskites. The subsequent discussion and comparison focus on the crystal symmetry, local structure, and order-disorder transitions. Pressure-tailored physical properties such as the bandgap, carrier lifetime, electronic resistance, and photocurrent are reviewed, and a detailed structure-property relationship is clarified. In addition, novel pressure-driven properties in known perovskites are investigated including metallization, indirect-direct bandgap exchanges, and the Shockley-Queisser optimal bandgap in lead-based perovskites, which was achieved for the first time. Furthermore, ambient properties in various photovoltaic perovskites are surveyed from a practical perspective, with an emphasis on how to employ pressure engineering on light-absorber materials applications and future materials-by-design. The study concludes by summarizing some challenges in the field and proposes potential future research topics.

“We hope this article gives a clearer picture of the exciting developments in this cutting-edge field,” said Dr. Gang Liu.