TOPCon accounts for 58% of global module shipments in 2026 and is the default choice for utility and C&I projects. This guide gives you everything needed to specify and buy the right TOPCon panel.
Global TOPCon share 2026
58%
vs 14% in 2023
Mainstream cell efficiency
25.2%
620W 78-cell
Temperature coefficient
-0.29%/°C
vs -0.34% PERC
Bifaciality factor
80–85%
typical
How TOPCon differs from PERC
Diagram
PERC vs TOPCon vs HJT cell cross-section
TOPCon replaces PERC's rear passivation stack with a tunnel oxide (~1.4 nm SiO₂) plus doped polysilicon layer, delivering near-perfect rear-side passivation and lifting open-circuit voltage by 20–35 mV. The result is 2.5–3.0 percentage points higher cell efficiency and materially better temperature and low-light behaviour.
Specification checklist
- Cell format: M10 (182 mm) or G12R (rectangular) — G12R growing fast
- Layout: 72c / 78c / 66c — match to your inverter string design
- Wattage bin: 585W / 605W / 620W with 0/+5W tolerance
- Bifaciality: ≥80%, glass-glass or transparent backsheet
- Encapsulant: POE for high-humidity climates, EVA acceptable for temperate
- Warranty: ≥25 years product, ≥30 years linear (0.4%/yr max)
Pricing
| Wattage | FOB China | CIF EU | CIF LATAM |
|---|---|---|---|
| 585W bifacial | $0.104/W | $0.113/W | $0.126/W |
| 605W bifacial | $0.107/W | $0.116/W | $0.129/W |
| 620W bifacial | $0.108/W | $0.117/W | $0.130/W |
Frequently asked questions
QIs TOPCon backward compatible with existing PERC strings?
Voltage and current ranges overlap for most inverters. Recheck string length against your inverter's max DC input — N-type modules typically have 3–5% higher Voc.
QHow much bifacial gain should I plan?
5–15% depending on albedo. High-albedo desert or snow: 12–18%. Standard ground-mount on grass: 5–8%. Rooftop with dark membrane: <3% — don't pay a bifacial premium.
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