Chinese polysilicon and photovoltaic module manufacturer Tongwei announced that its 770 W module based on tunnel oxide passivated contact (TOPCon) technology has achieved a bifaciality rate 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. Tongwei stated in a press release that a higher bifaciality rate 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 to standard modules, this configuration can generate an additional €180,000 ($205,844) in revenue annually and produce 81.62 million kWh more clean electricity over the plant's lifetime.

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

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