Hydrophobic Polystyrene Passivation Layer for Simultaneously Improved Efficiency and Stability in Perovskite Solar...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Long-term stability remains a key challenge for commercializing high-performance hybrid metal halide perovskite solar cells.
• The interface between the perovskite film and the organic charge-transfer layer is particularly vulnerable, impacting device longevity.
• Interface engineering is a promising strategy to enhance both efficiency and stability in perovskite solar cells.

Purpose of the Study:

• To investigate the impact of an interfacial polystyrene layer on the performance and stability of perovskite solar cells.
• To determine if polystyrene can effectively passivate interface defects and reduce non-radiative recombination.
• To assess the influence of the polystyrene layer on carrier dynamics and photovoltaic parameters.

Main Methods:

• Fabrication of perovskite solar cells with an inserted polystyrene interfacial layer between the perovskite and spiro-OMeTAD layers.
• Characterization of photovoltaic performance, including power conversion efficiency and current density-voltage hysteresis.
• Evaluation of interface properties through photoluminescence intensity and carrier lifetime measurements.
• Assessment of long-term stability under ambient conditions without encapsulation.

Main Results:

• The introduction of a polystyrene layer effectively passivates interface traps and defects, reducing non-radiative recombination.
• Enhanced photoluminescence intensity and carrier lifetime were observed in devices with the polystyrene layer.
• Perovskite solar cells with the optimized polystyrene layer achieved an average power efficiency of 19.61% (best 20.46%), an improvement from 17.63%.
• Devices exhibited negligible current density-voltage hysteresis and maintained 85% of their initial efficiency after 2 months of storage in open air.

Conclusions:

• An interfacial polystyrene layer is an effective strategy for simultaneously improving the efficiency and long-term stability of perovskite solar cells.
• Polystyrene's ability to passivate defects and reduce recombination contributes to enhanced photovoltaic performance.
• The hydrophobic nature of polystyrene enhances device stability, making it a promising approach for commercial applications.