High-Efficiency Solar Cell Design Reduces Contact Resistance Loss

LONGi Green Energy, one of the world’s leading solar panel manufacturers, has developed an improved solar cell design that addresses a persistent efficiency problem in photovoltaic technology. By strategically engineering the interface between critical layers, the company achieves better energy band matching and significantly reduces contact resistance losses, translating to meaningfully higher conversion efficiency.

The Problem

All solar cells face a fundamental challenge: converting sunlight into electrical current while minimizing energy losses during that conversion process. The conversion process requires multiple carefully engineered layers – a carrier transport layer that directs electrons, and a carrier collection layer that gathers and removes those electrons.

Currently, polysilicon layers at the interface between transport and collection layers create problematic contact resistance. This resistance causes energy losses as electrons flow through the interface, reducing the overall photoelectric conversion efficiency of the cell. For solar manufacturers operating in an intensely competitive market where efficiency improvements of just fractions of a percent provide meaningful cost advantages, this contact resistance problem represents significant lost revenue.

What This Invention Does

LONGi’s solution uses amorphous silicon regions strategically placed within the polysilicon layer of the transport layer. The key innovation is positioning these amorphous regions to contact the collection layer, rather than having pure polysilicon interface with the collection layer.

Amorphous silicon provides superior energy band matching at the interface, meaning electrons flow more naturally from the silicon substrate through the transport layer into the collection layer. This improved energy band alignment dramatically reduces the contact resistance that would otherwise occur at this critical interface.

The result is a solar cell that more efficiently converts sunlight into electrical current. The amorphous silicon region serves as an optimized interface layer that reduces parasitic resistive losses while maintaining structural integrity and electrical performance.

Key Features

Amorphous Silicon Interface Layer. Strategic placement of amorphous silicon in contact with the carrier collection layer provides superior energy band matching compared to pure polysilicon interfaces.

Contact Resistance Reduction. Lower contact resistance at the transport-collection layer interface means more electrical current flows with less energy dissipation, directly improving conversion efficiency.

Energy Band Optimization. The amorphous silicon region implements better energy-band matching between the silicon substrate carrier generation and the carrier collection process.

Enhanced Photoelectric Conversion. The combination of reduced contact resistance and optimized energy band matching delivers measurably improved photoelectric conversion efficiency in the completed cell.

Manufacturing Compatibility. The design works within existing photovoltaic manufacturing frameworks, making it adoptable by producers of different sizes without requiring entirely new equipment.

Layer Architecture Flexibility. The first transport layer design can be applied to one or both surfaces of the silicon substrate, allowing optimization for different panel configurations.

Who Is Behind It?

LONGi Green Energy Technology Co., Ltd. is one of the world’s largest solar cell and panel manufacturers, headquartered in China. The invention was developed by a team of eight engineers: Sun Zhaoqing, Zhou Shenghou, Tang Xiyan, Li Junjun, He Bingxuan, Ye Feng, Xue Chaowei, and Fang Liang. The company filed a priority patent application in China on 5 September 2024 before extending protection to Australia in April 2025, indicating strong belief in the commercial value of this efficiency improvement.

Why It Matters

Solar panel efficiency is the metric that drives adoption. Every fractional percentage improvement in conversion efficiency reduces the cost per watt of solar energy, making it more competitive against fossil fuels and battery storage. For a major manufacturer like LONGi with tens of millions of panels produced annually, even modest efficiency gains translate to substantial competitive advantages and revenue increases.

The patent covers fundamental solar cell technology (IPC codes H10F 10/166, H10F 77/122, H10F 71/00, H10F 77/16, H10F 71/10), reflecting the core nature of this innovation. This efficiency improvement matters not just for LONGi’s commercial success, but for the broader goal of making solar energy the default choice for power generation globally. More efficient cells reduce the land area needed for equivalent power generation, lower installation costs, and accelerate the transition away from carbon-intensive energy sources.

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AU 2025234301 was published in the Australian Official Journal of Patents on 19 March 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.

Related Concepts

The efficiency of a solar cell depends on minimising losses at every interface in its layer stack. Contact resistance at the junction between the carrier transport layer and the collection layer is one such loss mechanism, where a mismatch in electronic band structure forces electrons to overcome an energy barrier, dissipating energy as heat. Amorphous silicon‘s disordered atomic structure creates a more gradual band transition that eases this barrier.

LONGi is consistently among the leaders in solar cell efficiency records, having demonstrated over 27% efficiency for monocrystalline silicon cells. Each incremental gain in efficiency reduces the cost per watt of installed solar capacity, reinforcing the energy transition economics.