Mono PERC vs TOPCon vs HJT — Solar Cell Technology Compared

The Three Dominant Technologies in 2026

The solar industry is transitioning from P-type Mono PERC to N-type technologies (TOPCon and HJT). Each has distinct advantages in efficiency, temperature performance, cost, and manufacturing maturity.

Technology Comparison

Feature	Mono PERC	N-type TOPCon	HJT
Cell structure	P-type, rear passivated	N-type, tunnel oxide passivated	N-type, amorphous Si heterojunction
Max cell efficiency	24.0%	26.5%	26.8%
Max module efficiency	21.8%	22.8%	22.5%
Temperature coefficient	−0.34 to −0.38%/°C	−0.29 to −0.32%/°C	−0.24 to −0.26%/°C
LID susceptibility	Yes (B-O defects)	Minimal	Minimal
PID resistance	Requires treatment	Inherent resistance	Inherent resistance
Bifacial capability	Limited (~70%)	High (~80%)	High (~85%)
Manufacturing cost	Lowest	Low-medium	Highest
Market share 2026	~35% (declining)	~55% (growing)	~10% (niche)
LONGi product	Hi-MO 6	Hi-MO 7, Hi-MO X6	N/A

Mono PERC — The Proven Workhorse

PERC (Passivated Emitter and Rear Cell) has been the industry standard for over a decade. It is the most cost-effective technology with the lowest manufacturing cost per watt. LONGi's Hi-MO 6 represents the best of PERC technology at up to 21.8% efficiency.

Best for: Budget-conscious projects, temperate climates, proven reliability.

N-type TOPCon — The New Standard

TOPCon (Tunnel Oxide Passivated Contact) adds an ultra-thin tunnel oxide layer to reduce recombination losses. It achieves higher efficiency than PERC while maintaining similar manufacturing costs. LONGi's Hi-MO 7 achieves 22.8% efficiency — the industry's highest for TOPCon.

Best for: Hot climates, maximum efficiency, long-term value, most projects in 2026.

HJT — The Premium Option

Heterojunction technology combines crystalline silicon with amorphous silicon layers, achieving the lowest temperature coefficients (−0.24%/°C). However, HJT is 20–30% more expensive to manufacture and has lower module-level efficiency than the best TOPCon panels.

Best for: Extreme hot-climate applications where the temperature coefficient justifies the premium.

Hot-Climate Performance Comparison

At 65°C module temperature (typical Middle East summer):

• Mono PERC (−0.36%/°C): 14.4% power loss → 85.6% of STC output
• TOPCon (−0.29%/°C): 11.6% power loss → 88.4% of STC output
• HJT (−0.25%/°C): 10.0% power loss → 90.0% of STC output

The Verdict for 2026

N-type TOPCon (LONGi Hi-MO 7) offers the best balance of efficiency, cost, and hot-climate performance for the vast majority of projects. HJT remains a niche premium option. Mono PERC continues to serve budget-conscious installations well.

Frequently Asked Questions

Is TOPCon better than PERC?

Yes. TOPCon offers higher efficiency, lower degradation, better hot-climate performance, and inherent PID/LID resistance — all at only 5–8% higher cost than PERC.

Is HJT better than TOPCon?

HJT has a better temperature coefficient but lower module efficiency and 20–30% higher cost than the best TOPCon panels. For most projects, TOPCon offers better value.

Will PERC become obsolete?

PERC is declining in market share but will remain available for several more years. It still offers the lowest cost per watt and is suitable for budget projects.