The Critical Role of Laser Technology in Photovoltaic Cell Manufacturing

As the photovoltaic (PV) industry continues to pursue higher conversion efficiency and lower manufacturing costs, process technology has become a decisive factor in cell performance and scalability. From PERC to TOPCon and HJT, and further toward perovskite and tandem solar cells, cell architectures are becoming increasingly complex while process windows grow narrower. Within this evolution, laser technology has shifted from a supporting tool to a core manufacturing capability that underpins multiple generations of high-efficiency PV cells.

In PERC production lines, laser ablation enables micron-level patterning of passivation layers to form stable local contacts. In TOPCon manufacturing, laser boron doping is widely regarded as a key pathway toward cell efficiencies exceeding 26%. In emerging perovskite and tandem cells, laser scribing directly determines whether large-area, high-uniformity production is achievable. With its non-contact nature, high precision, and minimal heat-affected zone, laser technology has become an indispensable enabler of efficiency improvement and manufacturing reliability across the PV industry.

Laser Technology as a Common Foundation for Advanced PV Manufacturing

As cell technologies advance, manufacturers face several shared challenges: finer structural features, more sensitive materials, and increasingly strict yield requirements. Laser processing addresses these challenges through a unique combination of capabilities:
* Non-contact processing, avoiding mechanical stress and micro-cracks
* Micron-level spatial control, suitable for fine and complex cell structures
* Localized, ultra-short energy input, minimizing thermal damage
* High compatibility with automation and digital process control
These attributes make laser technology a highly versatile and upgradeable process platform, applicable from conventional crystalline silicon cells to next-generation tandem architectures.

Key Laser Applications Across Mainstream Cell Technologies
1. PERC Cells: A Mature Laser Processing Model
The industrial success of PERC (Passivated Emitter and Rear Cell) technology is closely linked to large-scale laser processing. Laser ablation is used to selectively open the aluminum oxide passivation layer on the rear side, forming local back-surface contacts while preserving passivation performance.
Additionally, laser selective emitter (SE) doping enables localized heavy doping beneath front-side contacts, reducing contact resistance and typically improving cell efficiency by around 0.3%. The maturity and stability of these laser processes have supported long-term mass production and market dominance of PERC cells.

2. TOPCon Cells: Laser Boron Doping as a Breakthrough Process
TOPCon (Tunnel Oxide Passivated Contact) cells utilize N-type silicon wafers, offering inherent advantages in carrier selectivity and electrical performance. However, conventional high-temperature furnace-based boron diffusion presents challenges, including high energy consumption, slower throughput, and increased risk to tunnel oxide integrity.
Laser boron doping enables localized, ultra-fast heating, allowing boron atoms to diffuse selectively into designated regions without exposing the entire wafer to high temperatures. This approach significantly reduces contact resistance while maintaining passivation quality and is widely considered a critical process for pushing TOPCon efficiencies beyond 26%.

3. HJT Cells: Laser-Induced Annealing for Interface Optimization
HJT (Heterojunction) cells rely on amorphous silicon layers for excellent surface passivation. However, interface defects such as dangling bonds can still lead to carrier recombination.
Laser-induced annealing (LIA) uses controlled laser irradiation to activate hydrogen migration at the amorphous/crystalline silicon interface, repairing defects in situ. This process has been shown to improve open-circuit voltage (Voc) and fill factor (FF), making it a practical method for HJT efficiency optimization.

4. Perovskite and Tandem Cells: Laser Scribing for Scalable Integration
In perovskite and perovskite/silicon tandem cells, laser processing is not only a manufacturing tool but also a structural enabler. Standard P1, P2, and P3 laser scribing steps define electrode segmentation, sub-cell isolation, and series interconnection.
Given the fragile nature and varied thermal stability of functional layers, laser processing—with its non-contact and high-precision characteristics—is essential for achieving high efficiency and uniformity in large-area devices. As a result, laser scribing is considered one of the core processes for tandem cell industrialization.

General-Purpose Laser Processes for Cost Reduction and Yield Improvement
Beyond cell-specific applications, laser technology also supports several cross-platform manufacturing steps:
* Laser-based gridline transfer: Enables finer electrodes and improved consistency compared to screen printing, significantly reducing silver paste consumption, especially in low-temperature processes such as HJT.
* Damage-free laser dicing: Allows precise half-cell and multi-cut processing with reduced micro-crack risk, improving module power output.
* Laser edge isolation and passivation: Repairs edge damage after cutting, reducing recombination losses and contributing to module-level efficiency gains.
These general laser processes play an important role in lowering cost per watt while improving overall manufacturing yield.

Thermal Management: The Foundation of Stable Laser Processing
As PV manufacturing moves toward higher throughput and long-duration continuous operation, laser process stability becomes increasingly dependent on precise thermal control. Even minor fluctuations in laser output can directly affect contact resistance, defect density, or line width consistency.
In production environments, laser sources and optical components operate under sustained thermal loads. Reliable cooling and temperature control systems are therefore essential to maintaining laser energy stability, minimizing power drift, and ensuring repeatable processing results. Effective thermal management of laser sources, power modules, and optical assemblies contributes directly to higher yield and process robustness, particularly for TOPCon, HJT, and tandem cells with narrower process margins.
Industrial temperature control solutions developed for high-power laser applications continue to evolve toward greater stability, faster response, and long-term operational reliability, providing a solid foundation for advanced PV manufacturing.

Conclusion
From the large-scale commercialization of PERC cells to the rapid adoption of TOPCon and HJT technologies, and onward to the exploration of tandem architectures, laser technology consistently runs through the most critical steps of photovoltaic cell manufacturing. While it does not define the theoretical efficiency limit, it strongly determines whether that efficiency can be produced consistently, controllably, and at scale.
As the PV industry advances toward higher efficiency and greater manufacturing reliability, laser processing, together with the system-level support that ensures its stability, will remain a fundamental driver of technological progress and industrial upgrading.