Effects of Annealing Conditions on Mixed Lead Halide Perovskite Solar Cells and Their Thermal Stability Investigation

In this work, efficient mixed organic cation and mixed halide (MA(0.7)FA(0.3)Pb(I0.9Br0.1)(3)) perovskite solar cells are demonstrated by optimizing annealing conditions. AFM, XRD and PL measurements show that there is a better perovskite film quality for the annealing condition at 100 degrees C for 30 min. The corresponding device exhibits an optimized PCE of 16.76% with V-OC of 1.02 V, J(SC) of 21.55 mA/cm(2) and FF of 76.27%. More importantly, the mixed lead halide perovskite MA(0.7)FA(0.3)Pb(I0.9Br0.1)(3) can significantly increase the thermal stability of perovskite film. After being heated at 80 degrees C for 24 h, the PCE of the MA(0.7)FA(0.3)Pb(I0.9Br0.1)(3) device still remains at 70.00% of its initial value, which is much better than the control MAPbI(3) device, where only 46.50% of its initial value could be preserved. We also successfully fabricated high-performance flexible mixed lead halide perovskite solar cells based on PEN substrates.