Dimensional Engineering: Another Approach To Resolving The Stability Issue Of High-efficiency Perovskite Solar Cells

Perovskite solar cell has shown rapid development in the past few years, and its features of low cost and high efficiency make it promising to at least partially replace silicon solar cell for energy harvesting in both industry and daily life.

However, despite the high expectation for such an excellent energy material, the stability issues have hindered the pace of progress. Tremendous efforts have been focused on investigating the material compositions that are efficient and stable. Among them, the 2D perovskite materials received considerable attention due to their unique structure, compatible electronic properties and, importantly, good stability.

In a recent paper published in Advanced Energy Materials, researchers from the Hong Kong University of Science and Technology reported the introducing of graded 2D-3D perovskite interface by employing an easy solution process. After optimization, the stability of the solar cell device is strongly enhanced, which keeps more than 60% of its initial efficiency when stored in the ambient atmosphere without encapsulation while the traditional device destroyed completely within 10 days.

Another substantial progress reported in this work shows that the function of 2D perovskite material is more than protect the device from moisture. The perovskite materials are plagued by strong ion migration, which is also a killer inside the device itself. The creation of the 2D structure significantly hindered the cross-layer ion migration which protects the metal electrode and prevents the decomposition of perovskite layer, giving strong protection for the device from both outside and inside of the film.

Benefited from the energy level adjustment, a high photoconversion efficiency of 19.89% with an ultrahigh Voc of 1.17 V is achieved from the more stable graded 2D-3D device. The design of this work combines the material and interface engineering and provides a new insight to improving perovskite solar cell performance from both efficiency and stability.

The work is led by Prof. Shihe Yang and his Post-Doctoral Fellow Dr. Yang Bai at the Hong Kong University of Science and Technology.

The study, Dimensional Engineering of a Graded 3D–2D Halide Perovskite Interface Enables Ultrahigh V_oc Enhanced Stability in the p-i-n Photovoltaics was recently published in the journal Advanced Energy Materials.