Chinese Researchers Engineer Novel Passivation Strategy for High-Efficiency Perovskite/Silicon Tandem Solar Cells

Chinese Academy of Sciences China

Overview

A Chinese research team has developed a novel passivation strategy that significantly boosts the efficiency and operational stability of perovskite/silicon tandem solar cells. By employing polystyrene nanospheres as a template, they precisely deposited a thin aluminum oxide insulating layer on pyramid-textured silicon substrates, effectively blocking electrical leakage pathways. This innovation achieved a certified power conversion efficiency of approximately 33% in 1 cm² cells, maintaining about 90% of their initial efficiency after 1,000 hours of continuous operation.

In Depth

Background and Challenges

Perovskite/silicon tandem solar cells hold immense promise for next-generation photovoltaics due to their potential for high power conversion efficiencies (PCEs). However, realizing their full commercial potential has been hindered by two critical challenges: achieving consistently high efficiencies and ensuring long-term operational stability. A major contributor to instability, particularly in devices utilizing pyramid-textured silicon substrates, is electrical leakage pathways created by the uneven surface topography. These shunting paths exacerbate degradation under environmental stresses such as humidity and elevated temperatures, significantly compromising the device’s lifespan.

Key Findings and Technical Advancements

Researchers at the Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, in collaboration with Suzhou University and Taizhou University, have introduced a groundbreaking passivation strategy to address this issue. Their approach involves using polystyrene nanospheres as a precise template to deposit an ultrathin aluminum oxide (Al₂O₃) insulating layer via atomic layer deposition (ALD) selectively on the peaks of the textured silicon surface. This ‘peak-selective passivation’ method is highly effective in:

• Blocking parasitic electrical shunts localized at the silicon surface asperities.
• Optimizing contact resistance and enhancing carrier transport kinetics across the interface.
• Achieving a certified PCE of 32.89% (reported at approximately 33%) for a 1 cm² active area device, representing a new benchmark in tandem cell performance.
• Demonstrating exceptional operational stability, retaining approximately 90% of initial efficiency after 1,000 hours of continuous operation, a significant improvement over previous technologies.

Impact and Outlook

This technical breakthrough is pivotal for accelerating the commercialization of perovskite/silicon tandem solar cells. The ability to effectively mitigate electrical leakage on complex textured surfaces, a challenge that conventional passivation methods struggled with, paves the way for scalable manufacturing of large-area modules. The research team suggests that this strategy is broadly applicable to other types of tandem solar cells and optoelectronic devices, potentially catalyzing innovation across the broader photovoltaic sector. Future efforts will likely focus on further upscaling the technology and optimizing cost-efficiency for industrial deployment, reinforcing China’s leadership in advanced solar research.