The photovoltaic industry has entered the "TWh era", and the continuous reduction of levelized cost of electricity (LCOE) relies on revolutionary breakthroughs in conversion efficiency. Perovskite-silicon tandem solar cells, with the advantage of a theoretical efficiency exceeding 43%, have become the core development direction of the third-generation photovoltaic technology. By organically combining wide-bandgap perovskite materials with narrow-bandgap silicon-based materials, this technology realizes efficient segmented utilization of the solar spectrum. Its efficiency ceiling is much higher than that of traditional monocrystalline silicon cells, providing a new possibility for the parity of photovoltaic power.

Currently, the large-scale application of this technology faces three core bottlenecks: insufficient open-circuit voltage caused by interface charge recombination, uniformity issues in large-area fabrication, and weather resistance defects of packaging materials. To address the interface problem, R&D teams have constructed interface modification layers through gradient-doped metal halides, effectively solving the energy level mismatch between perovskite and silicon heterojunctions. A breakthrough has been achieved by increasing the open-circuit voltage to over 1.9V, significantly reducing energy loss during charge transport.

Uniformity in large-area fabrication is a key obstacle restricting the mass production of tandem solar cells. Under traditional processes, the efficiency deviation of battery cells larger than 1 square meter often exceeds 5%. The development of roll-to-roll (R2R) vapor deposition technology has brought a new turn. This process can precisely control the thin-film growth environment, reducing the pinhole rate of perovskite thin films from over 2% to below 0.5%, and significantly reducing the number of grain boundary defects. It has successfully achieved the goal of efficiency deviation less than 3% for 1.2m×1.2m size battery cells.

Long-term stability determines the commercial value of tandem solar cells. Humid and hot environments as well as ultraviolet radiation can easily lead to rapid efficiency degradation of modules. The innovative design of organic-inorganic composite packaging structure reduces the water vapor transmission rate from 10⁻³g/m²/day to below 10⁻⁵g/m²/day. Combined with anti-ultraviolet coating technology, the modules can still ensure that the efficiency degradation is less than 20% within 25 years under extreme working conditions of -40℃ to 85℃, meeting the long-term operation needs of photovoltaic power plants. It is predicted that by 2030, the global market share of tandem solar cells will exceed 30%, and with the continuous optimization of process costs, it is expected to promote the LCOE of photovoltaics to below 0.1 yuan.

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