Rigid perovskite solar cells (PSCs) have attracted attention due to their high conversion efficiency (PCE) as high as 25.7%. However, flexible PSCs have not achieved the same success due to a PCE of only 22.4% and less stability.

     In a study published in Advanced Materials in November 2022, the researchers modified the interface between the perovskite and the hole transport layer (HTL) by using Pentylammonium Acetate (PenAAc) molecules. Through the synthesis of anions and cations, the researchers found that both PenA⁺ and Acˉ have strong chemical bonds with the defects on the surface of the perovskite film.

   The researchers use Enlitech solar simulator and QE-R quantum efficiency measurement system. The findings confirm that the PenAAc-modified flexible PSC achieves a record PCE of 23.68% with a high open-circuit voltage (Voc ) of 1.17 V. The large-area device (1.0 cm² ) also achieves an excellent PCE of 21.52%. Through the function of automatically adjusting the light intensity of the Enlitech solar simulator, it is very convenient to obtain Sun-Voc data. Moreover, even after 5000 bending cycles, the PCE still retains more than 91% of the original PCE, demonstrating the excellent stability of the device under mechanical bending.