Explore the vast range of titles available.

Development of suitable hole transport materials is vital for perovskite solar cells (PSCs) to diminish the energy barrier and minimize the potential loss. Here, a low-cost hole transport molecule named SFX-POCCF3 (23.72 $/g) is designed with a spiro[fluorene-9,9'-xanthene] (SFX) core and terminated by trifluoroethoxy units. Benefiting from the suitable energy level, high hole mobility, and better charge extraction and transport, the PSCs based on SFX-POCCF3 exhibit improved open-circuit voltage by 0.02 V, therefore, the PSC device based on SFX-POCCF3 exhibits a champion PCE of 21.48%, which is comparable with the control device of Spiro-OMeTAD (21.39%). More importantly, the SFX-POCCF3 based PSC possesses outstanding light stability, which retains 95% of the initial efficiency after about 1,000 h continuous light soaking, which is in accordance with the result continuous output at maximum power point. Whereas, Spiro-OMeTAD witnesses a rapid decrease to 80% of its original efficiency after 100 h light soaking. This work demonstrated that an efficient alignment of energy levels between HTL and perovskite will lead to significant highly efficient PSCs with remarkably enhanced light stability.