Toward Understanding the Built-in Field in Perovskite Solar Cells through Layer-by-Layer Surface Photovoltage...

Area of Science:

• Materials Science
• Solid State Physics
• Renewable Energy

Background:

• The built-in voltage (V_BI) is crucial for solar cell performance.
• Understanding V_BI in perovskite solar cells is limited.
• Perovskite solar cells offer promising renewable energy solutions.

Purpose of the Study:

• Systematically investigate the V_BI in pin-type perovskite solar cells.
• Determine the origin and contribution of different layers to V_BI.
• Establish a reliable method for analyzing V_BI.

Main Methods:

• Layer-by-layer surface photovoltage (SPV) measurements.
• Kelvin probe (KP) and ultraviolet photoelectron spectroscopy (UPS) for work function (WF) analysis.
• Simulations to reproduce experimental data.

Main Results:

• SPV increases with each added layer, equaling the open-circuit voltage (V_OC) in full devices.
• Transport layers (HTL/ETL) contribute moderately (100-200 meV) to SPV.
• The top metal electrode significantly contributes to SPV (≈500 meV), indicating V_BI is electrode-dependent.

Conclusions:

• V_BI in perovskite solar cells primarily arises from the work function difference between electrodes.
• Layer-by-layer SPV measurements are effective for understanding device energetics.
• This method aids in optimizing perovskite solar cell performance.