Breakthrough at Longyan University: Natural Chitosan Material Makes Perovskite Solar Cells More Efficient and Stable

With the growing global demand for clean energy, perovskite solar cells have become a research hotspot in the photovoltaic field due to their high efficiency and low cost. However, defects within the bulk and at the interfaces of the devices have long constrained further improvements in device performance and operational lifespan. Recently, a research team led by He Qianqian and Lu Xiaochun from the College of Chemistry and Material Science at Longyan University published a study in Guangdong Chemical Industry, offering a new approach to address this challenge.

The study innovatively introduces a natural polymer material—carboxymethyl chitosan (CMCS)—into the tin oxide electron transport layer. Chitosan is widely available, green, and environmentally friendly. The abundant carboxyl and hydroxyl functional groups on its molecular chains can strongly chelate with lead ions in the perovskite film, achieving two effects: first, effectively passivating interface defects within the film and reducing non-radiative recombination losses; second, promoting the growth of perovskite grains, resulting in a denser and more uniform film with significantly reduced grain boundaries.

The research team systematically investigated the effect of different CMCS concentrations on device performance. The results showed that the optimal device performance was achieved at a CMCS concentration of 1.0 mg/mL. After CMCS modification, the power conversion efficiency of the perovskite solar cells increased significantly from 6.51% in the control group to 10.14%, representing an improvement of over 55%. Meanwhile, the external quantum efficiency of the devices also increased from 70.10% to 80.70%, indicating more efficient utilization of photogenerated charge carriers.

In terms of stability, the introduction of CMCS also brought significant improvements. After 48 days of storage under ambient conditions without encapsulation, the CMCS-modified devices retained 88.32% of their initial efficiency, while the unmodified control group retained only 65.37%. This improvement is attributed to the effective passivation of interface defects by CMCS and the increase in perovskite grain size, which together reduce non-radiative recombination and leakage current within the devices.

Using natural biomass materials with a simple and environmentally friendly process, this study not only significantly enhances the photovoltaic performance and long-term stability of all-inorganic perovskite solar cells but also provides a new technical pathway for the future development of low-cost, high-efficiency perovskite photovoltaic devices, offering important potential for practical applications.