Identifying the charge generation dynamics in Cs⁺-based triple cation mixed perovskite solar cells

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Triple cation perovskite solar cells demonstrate superior moisture tolerance and stability over mixed perovskite counterparts.
• Cesium (Cs+) incorporation, due to its smaller ionic size, effectively mitigates halide segregation issues in perovskite formulations.

Purpose of the Study:

• To investigate the device kinetics and fundamental role of cesium (Cs+) in triple cation perovskite solar cells.
• To correlate nanoscale properties with overall device performance under operational conditions.

Main Methods:

• Utilized various scanning probe microscopy techniques, including Kelvin probe force microscopy.
• Performed electrochemical impedance spectroscopy (EIS) to analyze charge carrier dynamics.
• Investigated nanoscale current generation under illumination.

Main Results:

• Cesium (Cs+) incorporation significantly increased the contact potential difference (CPD), with further enhancement observed upon Spiro-OMeTAD deposition.
• Nanoscale current measurements showed marked improvement with Cs+ inclusion and Spiro-OMeTAD, supporting higher photocurrent densities.
• Electrochemical impedance spectroscopy revealed reduced carrier recombination at the TiO2/perovskite interface in triple cation devices.

Conclusions:

• Cesium (Cs+) plays a crucial role in enhancing the stability and performance of perovskite solar cells.
• The combination of triple cation composition and Spiro-OMeTAD as a hole transport layer optimizes device kinetics, leading to improved V_oc and photocurrent.
• Understanding these nanoscale effects provides pathways for developing more efficient and durable perovskite solar technologies.