Enhancing Crystallization in Hybrid Perovskite Solar Cells Using Thermally Conductive Two-Dimensional Boron Nitride Nanosheet Additive

Citation

Yin, Y.; Zhou, Y.; Fu, S.; Zuo, X.; Lin, Y.-C.; Wang, L.; Xue, Y.; Zhang, Y.; Tsai, E.; Hwang, S.; Kisslinger, K.; Li, M.; Cotlet, M.; Li, T.-D.; Yager, K.G.; Nam, C.-Y.; Rafailovich, M.H. "Enhancing Crystallization in Hybrid Perovskite Solar Cells Using Thermally Conductive Two-Dimensional Boron Nitride Nanosheet Additive" Small 2023, 19 2207092.
doi: 10.1002/smll.202207092

Summary

We demonstrate how adding hBN nanosheets to perovskites can improve ordering.

Abstract

Controlling crystallization and grain growth is crucial for realizing highly efficient hybrid perovskite solar cells (PSCs). In this work, we demonstrate enhanced PSC photovoltaic performance and stability by accelerating perovskite crystallization and grain growth via two-dimensional (2D) hexagonal boron nitride (hBN) nanosheet additives incorporated into the active perovskite layer. In-situ X-ray scattering and infrared thermal imaging during the perovskite annealing process revealed the highly thermally conductive hBN nanosheets promoted the phase conversion and grain growth in the perovskite layer by facilitating a more rapid and spatially uniform temperature rise within the perovskite film. Complementary structural, physicochemical, and electrical characterizations further showed that the hBN nanosheets formed a physical barrier at the perovskite grain boundaries and the interfaces with charge transport layers, passivating defects and retarding ion migration. As a result, the power conversion efficiency of the PSC was improved from 17.4% to 19.8%, along with enhanced device stability, retaining ~90% of the initial efficiency even after 500 h ambient air storage. The results not only highlight 2D hBN as an effective additive for PSCs but also suggest the enhanced thermal transport as one of the pathways for the improved PSC performance by 2D material additives in general.