Toward high-efficiency stable 2D/3D perovskite solar cells by incorporating multifunctional CNT:TiO2 additives into 3D perovskite layer

The power conversion efficiency (PCE) of 2D/3D perovskite solar cells (PSCs) is still significantly low compared with 3D PSCs due to the poor charge transport ability of 2D perovskite thin films and a large number of defects in 3D thin films. Herein, to address these two issues, multifunctional TiO2 nanoparticles (NPs)-modified carbon nanotubes (CNT:TiO2 ) additives are incorporated into 3D perovskite layer for the first time, and demonstrate three positive effects for CNT:TiO2 material application: firstly, it passivates the defect state of the 3D perovskite layer and enhances the charge mobility of the 3D layer; secondly, its interaction with the 2D film increases the conductivity of the 2D layer and produces the interface polarization electric field to promote the hole extraction. As a consequence, not only the PCE of the optimized 2D/3D PSCs with the CNT:TiO2 is greatly improved to 22.7% from 19.8% of the control PSCs, but also the stability is significantly improved.

Automated summary

By incorporating CNT:TiO2 additives into 3D perovskite solar cells, the efficiency and stability of 2D/3D perovskite solar cells can be improved. CNT:TiO2 materials can passivate the defect state of the 3D perovskite layer, enhance charge mobility in the 3D layer, and increase conductivity in the 2D layer, leading to improved overall performance of perovskite solar cells.