Highly Efficient CsPbBr₃ Planar Perovskite Solar Cells via Additive Engineering with NH₄SCN

Area of Science:

• Materials Science
• Photovoltaics
• Solid-State Chemistry

Background:

• Perovskite solar cells (PSCs) require enhanced stability for commercial viability.
• All-inorganic CsPbBr3 perovskites offer excellent stability but suffer from low light absorption and charge recombination, limiting efficiency.
• Current efficiencies of CsPbBr3 PSCs lag behind organic-inorganic hybrid counterparts.

Purpose of the Study:

• To improve the quality and performance of CsPbBr3 perovskite films for solar cell applications.
• To investigate the effect of NH4SCN as an additive on CsPbBr3 film properties and device performance.
• To enhance the power conversion efficiency (PCE) and stability of CsPbBr3 planar PSCs.

Main Methods:

• Fabrication of CsPbBr3 films using additive engineering with ammonium thiocyanate (NH4SCN).
• Characterization of film morphology, crystallinity, and trap state density.
• Photoluminescence and electrochemical analyses (impedance spectroscopy, space-charge limited current, Mott-Schottky) to assess charge dynamics.
• Fabrication and testing of CsPbBr3 planar PSC devices.

Main Results:

• NH4SCN incorporation resulted in smooth, dense CsPbBr3 films with improved crystallinity and reduced trap state density.
• The additive effectively suppressed interface recombination and promoted charge transport within the device.
• CsPbBr3 planar PSCs with 1.5% NH4SCN additive achieved a champion PCE of 8.47%, compared to 7.12% for the pristine device.

Conclusions:

• Additive engineering with NH4SCN is a viable strategy to enhance the performance of CsPbBr3 perovskite solar cells.
• NH4SCN improves film quality and charge carrier dynamics, leading to higher power conversion efficiencies.
• This approach offers a pathway towards more efficient and stable all-inorganic perovskite solar cells.