TOPCon bifacial PV learning centre
Modern N-type TOPCon bifacial modules combine a passivated rear contact with glass-glass construction to improve efficiency, temperature behaviour and rear-side energy harvest.
1) Photons above the silicon band gap are absorbed. 2) Electron-hole pairs are created. 3) The p-n junction electric field separates charge. 4) Metal contacts collect DC current. 5) Series/parallel cells create module voltage and current.
A very thin tunnel-oxide layer and doped poly-silicon contact reduce surface recombination while allowing carrier transport. Commercial module efficiency may exceed 22%, but use the exact manufacturer data sheet rather than a generic claim.
Rear cells collect reflected light from roof/ground albedo. Gain depends on surface reflectance, module height, row spacing, shading and mounting. Glass-glass modules protect both sides and can improve durability; bifacial gain is not guaranteed without site modelling.
Indicative module ranges: Mono PERC 20-22% efficiency and about -0.35%/°C; N-type TOPCon 21.5-23.5% and about -0.29%/°C; HJT 21.5-24% and about -0.24%/°C. Exact figures vary by model and test conditions.
Tempered glass, encapsulant, cells, rear glass/backsheet, aluminium frame, junction box and bypass diodes form the module. MC4-compatible connectors, UV-resistant DC cable, mounting structure, earthing, lightning/SPD protection, DCDB, inverter, ACDB and meter complete the plant.
Sunlight → PV cell → DC strings → DC protection → MPPT inverter → AC protection → appliances / net meter / grid. Off-grid adds a charge controller or hybrid inverter and battery between generation and loads.