A First! Breakthrough Progress in China's Solar Cell Sector

On October 28, reporters learned from Nanjing University that a research team led by Assistant Professor Lin Renxing and Professor Tan Hairen has designed an all-perovskite tandem solar cell fabricated using a dipole passivation strategy. Certified by the internationally recognized Japanese Electrical Safety & Environment Technology Laboratories, this cell achieved a photoelectric conversion efficiency of 30.1%—marking the first time the conversion efficiency of polycrystalline thin-film solar cells has surpassed 30%. This result has been included in the "Solar Cell Efficiency Tables," and the related findings were published in the international academic journal Nature on October 28.

In this research, scientists identified the interface between the perovskite light-absorbing layer and the hole transport layer as a region with significant carrier loss. To address this, the team designed a dipole passivation layer. This layer functions like a one-way street in a city, connecting the perovskite light-absorbing layer on one end and the hole transport layer on the other, directing carriers toward the hole transport layer.

Terahertz radiation detection and diagnostic results clearly revealed the microscopic mechanisms of the dipole passivation strategy in promoting charge transport and suppressing losses. Experimental data showed that the passivated perovskite film achieved a total carrier mobility increase of over 68% and an extension of the carrier diffusion length by nearly 30%.

The research innovatively proposed a new concept for a "matrix-confined molecular layer" type hole transport layer configuration. This breakthrough overcomes the intrinsic limitations of molecular aggregation, stacking, and crystallization faced by traditional self-assembled monolayer-type hole transport layer systems. It establishes a new technical pathway for charge transport layers with broad molecular applicability and high process scalability, resolving challenges such as film inhomogeneity and interface instability encountered during the fabrication of perovskite photovoltaic modules based on self-assembled charge transport layers.

Ultimately, through collaboration with CATL's 21C Innovation Laboratory, the research successfully developed a large-scale 1m×2m perovskite photovoltaic module with a photoelectric conversion efficiency exceeding 20%, setting a new world record in the field.