The rigid structure of traditional photovoltaic modules limits their application in special scenarios. However, the breakthrough development of flexible silicon-based tandem solar cells has expanded the application boundary of photovoltaic technology from ground power stations to fields with light and flexible requirements such as space photovoltaics, vehicle-mounted photovoltaics, and building skins. Through the composite design of ultra-thin silicon wafers and perovskite materials, these cells achieve high conversion efficiency while possessing excellent mechanical flexibility, opening a new era where photovoltaics are "everywhere".

The core technological breakthrough of flexible batteries starts with the re-understanding of the properties of silicon materials. Traditional views hold that monocrystalline silicon is a rigid and brittle material, but studies have found that when the thickness of the silicon wafer is reduced to tens of microns (the thickness of traditional silicon wafers is usually 120-200 microns), the elastic deformation ability of its atomic structure is manifested—even if the bending radius is less than 2 cm, the surface stress of the silicon wafer is still lower than the intrinsic fracture threshold, and no cracks will occur. Based on this characteristic, ultra-thin silicon wafers with a thickness of 60 microns have become the ideal substrate material for flexible tandem solar cells, reducing the battery weight to less than 4.4 grams, with a power per unit weight of up to 1.77W/g.

The interface adaptation between the perovskite functional layer and the ultra-thin silicon wafer is the key to the technology. Repeated bending and temperature changes can easily lead to interface delamination failure. The "porous-dense" double-layer buffer structure innovatively designed by the R&D team effectively resolves this contradiction: the porous SnOx layer is like a "spring mattress", which can absorb and dissipate the ion bombardment force during preparation and mechanical stress during use; the dense SnOx layer ensures efficient extraction of interface charges and stable electrical connection, realizing the balance between flexibility and power generation performance.

At present, flexible silicon-based tandem solar cells have achieved significant performance breakthroughs. The efficiency of small-area devices has been certified by international authoritative institutions to reach 33.4%, and the efficiency of commercial-sized silicon wafer-level flexible cells has also exceeded 29.8%, making it the world's first and only certified flexible tandem solar cell efficiency record. This photovoltaic technology, which combines high power, light weight, and flexibility, has broad application prospects in fields such as new energy vehicle roof power generation, wearable device power supply, and spacecraft energy systems, opening up a new growth space for the photovoltaic industry.

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