Neutralizing Charge Centers Radius via Dipole-Charge Interaction in Perovskites

Area of Science:

• Materials Science
• Photovoltaics
• Solid-State Chemistry

Background:

• Organic-inorganic perovskite materials suffer from performance limitations due to unneutralized charge centers, like positively charged defects.
• Lattice imperfections, including point-vacancies and under-coordinated lead ions, create these detrimental charge centers, hindering photoelectric properties.

Purpose of the Study:

• To introduce a novel dipolar molecule, 3,3-difluoropyrrolidine hydrochloride (GOSO-005), for neutralizing positive charge centers in perovskites.
• To investigate the impact of GOSO-005 on perovskite defect density, charge transport, recombination rates, and overall device performance and stability.

Main Methods:

• Synthesis and characterization of the novel dipolar molecule 3,3-difluoropyrrolidine hydrochloride (GOSO-005).
• Incorporation of GOSO-005 into perovskite solar cell active layers to neutralize charged defects.
• Performance characterization of the modified perovskite solar cells, including power conversion efficiency (PCE) measurements.
• Assessment of device stability under various stress conditions (environmental, illumination, thermal).

Main Results:

• GOSO-005 effectively neutralizes positive charge centers by interacting with charged defects, reducing defect density.
• The neutralization strategy minimizes the effective electron-capturing radius, enhancing charge transport and reducing Shockley-Read-Hall recombination.
• Perovskite solar cells treated with GOSO-005 achieved a power conversion efficiency of 26.09% (certified 26.12%).
• The incorporation of GOSO-005 significantly enhanced the hydrophobicity of the perovskite, leading to improved long-term operational, illumination, and thermal stability.

Conclusions:

• 3,3-difluoropyrrolidine hydrochloride (GOSO-005) is a highly effective additive for passivating positive charge centers in perovskite solar cells.
• GOSO-005 treatment leads to substantial improvements in both the power conversion efficiency and the operational stability of perovskite devices.
• This charge neutralization strategy offers a promising pathway for developing more efficient and durable perovskite solar cell technologies.