Fabricating efficient and stable quasi-3D and 3D/2D perovskite solar cells with 2D-sheets connected by inorganic type ionic-bond

Area of Science:

• Materials Science
• Solid-State Chemistry
• Renewable Energy

Background:

• Perovskite solar cells (PSCs) offer promising photovoltaic performance.
• Enhancing the stability and efficiency of PSCs remains a key challenge.
• Two-dimensional (2D) perovskites are explored for improved device characteristics.

Purpose of the Study:

• To synthesize and characterize a novel 2D (SrBr)2PbI4 perovskite layered architecture.
• To investigate the application of 2D (SrBr)2PbI4 as a passivation layer in 3D perovskite solar cells.
• To evaluate the power conversion efficiency (PCE) and long-term stability of the fabricated solar cells.

Main Methods:

• Synthesis of 2D (SrBr)2PbI4 via reaction of strontium bromide (SrBr2), strontium iodide (SrI2), and lead iodide (PbI2).
• Structural characterization using small-angle X-ray diffraction (XRD) to confirm layer formation.
• Fabrication and testing of quasi-3D and 3D/2D perovskite solar cells.

Main Results:

• The 2D (SrBr)2PbI4 structure was confirmed by XRD with a layer spacing of 13.78 Å.
• Quasi-3D perovskite solar cells, (SrBr)2FA59Pb60I181 (n=60), achieved a PCE of 18.46% with 95% retention after 1000 h.
• 3D/2D perovskite solar cells (FAPbI3/(SrBr)2PbI4) demonstrated a PCE of 22.14% and retained over 90% efficiency after 1000 h in dry air.

Conclusions:

• Inorganic complex cations can form stable 2D perovskites.
• 2D (SrBr)2PbI4 serves as an effective surface passivation layer, reducing defects at the interface.
• The developed 3D/2D perovskite architecture offers a pathway towards highly efficient and stable perovskite solar cells.