Less Is More : Simplified Fluorene-Based Dopant-Free Hole Transport Materials Promote the Long-Term Ambient Stability of Perovskite Solar Cells
The stability of perovskite solar cells (PSCs) is greatly affected by the interface between the perovskite active layer and the hole transport material (HTM). The rational design of HTMs with effective anchoring to the perovskite surface is an emerging elegant strategy to promote compact and ordered interfaces that lead to highly efficient and stable PSCs. Herein, we propose two fluorene-based HTM