The proposed all-perovskite non-toxic cell structure is given in Figure (a) and the band alignment of ETM, Absorber, and HTM is given in Figure ). During simulation, the solar radiation spectrum is set as AM 1.5G with 300 o K temperature, and illumination is set to 1000W/m 2 for the simulation. The hole thermal velocity and electron thermal velocity are 1×10 7 cm/s while band-to-band recombination is taken as 2.3×10 -9 cm 3 /s. The interface layer between HTM/Absorber and Absorber/ETM is also taken into consideration.