PV Magazine, China's polysilicon and photovoltaic module manufacturer Tongwei has announced that its 770 W module based on tunnel oxide passivated contact (TOPCon) technology has achieved a bifaciality of 93.08%. This result sets a world record for bifacial technology and has been verified by German certification body TÜV Rheinland.

The module has a power conversion efficiency of 24.8% and a temperature coefficient of -0.26%/°C. In a statement, Tongwei said that higher bifaciality allows the module's rear side to generate more electricity, thereby providing additional energy yield. Taking a 100 MW solar power plant in Hamburg, Germany as an example, compared with standard modules, this configuration can generate an additional €180,000 ($205,844) in revenue per year and produce 81.62 million kWh of additional clean electricity over the plant's lifetime.

In July 2025, Tongwei announced a bifaciality of 91.7% on a 722 W TOPCon module. The company stated at the time that achieving 95% bifaciality on cells and 90% bifaciality on mass-produced modules was a significant challenge, but expected it to be reached within one to two years. This result was achieved using TOPCon cells with a bifaciality of 94.3%.

Company researchers explained that this achievement is attributed to two cell design innovations: estructura selectiva de pirámides hundidas (sunken pyramid selective structure) and contacto de pasivación con patrón de paso de cebra (zebra-step patterned passivation contact). The former optimizes the rear texture in the non-electrode area of the cell's rear side, while the latter improves the passivation effect of the n-type passivation contact based on polysilicon and silicon oxide (SiOx). Further details on this technological advancement have not yet been disclosed.