Vertically Oriented 2D Layered Perovskite Solar Cells with Enhanced Efficiency and Good Stability

Area of Science:

• Materials Science
• Solid-State Chemistry
• Renewable Energy

Background:

• Two-dimensional (2D) layered perovskites offer tunable properties for photovoltaic applications.
• Enhancing the efficiency and stability of 2D perovskite solar cells remains a critical research objective.
• Controlling film crystallinity and orientation is crucial for device performance.

Purpose of the Study:

• To develop a facile method for fabricating vertically oriented, highly crystalline 2D perovskite thin-films.
• To investigate the effect of ammonium thiocyanate (NH4SCN) additive on film properties and device performance.
• To assess the humidity stability and power conversion efficiency (PCE) of fabricated 2D perovskite solar cells.

Main Methods:

• One-step spin-coating process utilizing ammonium thiocyanate (NH4SCN) as an additive.
• Fabrication of 2D layered perovskite thin-films with the composition (BA)2(MA)n-1PbnI3n+1 (n=3, 4).
• Fabrication of photovoltaic devices with a standard structure including ITO, PEDOT:PSS, perovskite layer, PCBM, and Ag electrode.

Main Results:

• Vertically oriented, highly crystalline 2D perovskite films exhibited excellent humidity stability (unchanged XRD after 40 days).
• Devices based on (BA)2(MA)2Pb3I10 (n=3) achieved an average PCE of 6.82%.
• Devices based on (BA)2(MA)3Pb4I13 (n=4) achieved a higher PCE of 8.79% with remarkable stability in a nitrogen atmosphere.

Conclusions:

• The addition of NH4SCN is a simple and effective strategy to enhance the efficiency of 2D perovskite solar cells.
• The fabricated 2D perovskite films demonstrate promising stability under humid conditions and operational stability.
• This work presents a viable pathway for developing stable and efficient 2D perovskite photovoltaic devices.