Figure 4: Performance of the MAPbI₃ devices with PTAA HTL.

(a) The photocurrent of the MAPbI₃ devices under 1 sun illumination; (b) EQE of the devices with the active layers of MAPbI₃; (c) stabilized photocurrent measurement of the MAPbI₃ device with PTAA HTL under 1 sun illumination with light turned on and off by a shutter.