Perovskite solar module based on new interconnection tech achieves 21.37% efficiency

China-based perovskite solar cell and module manufacturer Mellow Energy, a spin-off of the Institute of New Energy Technology at Jinan University, has fabricated a monolithic perovskite solar module based on an interconnection technique that reportedly prevents the effusion of volatile components from the perovskite solar cell absorber.

“In monolithic perovskite solar modules, the migration of ions in the interconnect region is a critical factor that affects both efficiency and stability,” Shaohang Wu, a researcher at Jinan University, told pv magazine. “To address this issue, Jinan University and Mellow Energy have proposed an innovative method for in-situ generation of ion barrier layers, resulting in a substantial enhancement in efficiency and stability. This gas-phase treatment technique requires simple equipment, is user-friendly, and eliminates the need for additional coating processes, making it highly suitable for integration into production lines.”

The scientists fabricated the panel with an inverted perovskite cell based on an anti-diffusion layer, a substrate made of glass and indium tin oxide (ITO), a hole transport layer (HTL) made of poly-triarylamine (PTAA), a 3D-2D perovskite absorber hybridized with PoBx species, an electron transport layer (ETL) based on a buckminsterfullerene (C60) and tin(IV) oxide (SnO2), and a silver (Ag) metal. They interconnected the solar cells via P1, P2, and P3 scribes.

They explained that the ETL was deposited on the perovskite absorber via atomic layer deposition (ALD) to inhibit the vertical escape of volatile species. They then applied post-annealing to improve the redistribution and recrystallization of the perovskite composition. The 2D/3D heterostructure is aimed at accelerating the charge extraction at the perovskite/C60 interface and suppressing light-induced halide segregation.

“PbOx materials are directionally generated by selective growth using a gas-solid reaction method,” the scientists said. “And we have confirmed that PbOx can be a good barrier and passivation layer.”

Tested under standard illumination conditions, the solar cell achieved a power conversion efficiency of 21.37%, an open-circuit voltage of 7.195 V, a short-circuit current of 47.15 mA, and a fill factor of 80.89%. The device was also able to retain around 90% of its initial efficiency after 1,184 h.

The solar module and the related manufacturing process were described in the paper “Efficient and Stable Perovskite Solar Modules Enabled by Inhibited Escape of Volatile Species,” which was recently published in Advanced Materials. “This scheme provides a good idea for achieving efficient and stable perovskite photovoltaic modules in industry,” the research group stated.

Another research group at Jinan University recently unveiled a perovskite solar module with an efficiency of 21.07%. This device was fabricated through selective nanosecond-pulse and laser-induced ablation to obtain the high-quality interconnection.