Enhancing Optical and Electrical Performances via Nanocrystalline Si-Based Thin Films for Si Heterojunction Solar...

Area of Science:

• Materials Science
• Photovoltaics
• Semiconductor Devices

Background:

• Silicon heterojunction (SHJ) solar cells are a leading next-generation technology due to high efficiency and stability.
• The n-type carrier selective layer (electron-transport layer, ETL) is critical for SHJ solar cell performance, requiring high optical transmittance and conductivity.
• Optimizing the ETL is essential for maximizing solar energy conversion in SHJ devices.

Purpose of the Study:

• To investigate the optical and electrical properties of different n-type thin films for ETLs in SHJ solar cells.
• To evaluate the impact of monolayer, bilayer, and trilayer structures on SHJ solar cell performance.
• To identify an optimal ETL structure for high-efficiency and industrially viable SHJ solar cells.

Main Methods:

• Fabrication of n-type monolayer, bilayer, and trilayer Si-based thin films (n-nc-Si:H/n-nc-SiOx:H/n+-nc-Si:H) using plasma-enhanced chemical vapor deposition.
• Characterization of optical and electrical properties of the prepared thin films.
• Integration of optimized ETL structures into single-side rear-emitter SHJ solar cells and performance evaluation.

Main Results:

• The n-nc-Si:H/n-nc-SiOx:H/n+-nc-Si:H trilayer ETL structure demonstrated superior performance.
• The trilayer structure improved passivation contact, reduced parasitic absorption, and enhanced TCO contact.
• Achieved a conversion efficiency of 20.41% with an open-circuit voltage of 720 mV, short-circuit current density of 39.34 mA/cm², and fill factor of 72.05%.

Conclusions:

• The proposed trilayer ETL structure significantly enhances SHJ solar cell efficiency by optimizing optical and electrical properties.
• This structure offers a promising pathway for the industrial application of high-performance SHJ solar cells.
• The optimized ETL design contributes to efficient solar energy utilization.