Eliminating Non-Corner-Sharing Octahedral for Efficient and Stable Perovskite Solar Cells

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photovoltaics

Background:

• The metal halide (BX6)4- octahedron is the core unit in metal halide perovskites.
• The impact of octahedral connectivity on perovskite stability and optoelectronics is not fully understood.

Purpose of the Study:

• To investigate how different octahedral connectivities (corner-, edge-, face-sharing) in CsxFA1-xPbI3 perovskite films affect structural stability and optoelectronic properties.
• To explore tuning octahedral connectivity through compositional and additive engineering.

Main Methods:

• Compositional and additive engineering to tune octahedral connectivity in CsxFA1-xPbI3 perovskite films.
• Ultralow-dose transmission electron microscopy for reliable characterization of octahedral connectivity.
• Macroscopic device testing of solar cells fabricated from these films.

Main Results:

• Films with predominantly corner-sharing octahedra exhibit improved solar cell performance, longer charge carrier lifetimes, higher open-circuit voltage, and reduced hysteresis.
• Suppression of non-corner-sharing phases enhances structural, optoelectronic, and device performance stability.
• These improvements are observed even in films with identical chemical compositions, highlighting the critical role of connectivity.

Conclusions:

• Octahedral connectivity is a crucial parameter for enhancing the performance and stability of metal halide perovskite solar cells.
• Controlling connectivity offers a new strategy for designing advanced photovoltaic devices.
• This research provides a framework for understanding and manipulating perovskite structure-property relationships.