CH3NH3PbI3-based planar perovskite solar cells were fabricated by slot-die coating, a scalable method. Slot-die coating tends to produce perovskite layers with much lower coverage with overgrown crystals than spin coating, which does not include a self-drying mechanism in the process. To mimic the self-drying behavior inherent in spin coating, the present study introduces a blowing step in the slot-die coating method, which significiltly improved coverage of the prepared slot-die coated perovskite films. The slot-die-coated device with blowing showed a moderate power conversion efficiency (PCE) of 8.8%. The morphology of the slot-die-coated perovskite film is further improved by optimizing the deposition temperature. The combination of blowing rand heating during the slot-die-coating step and the introduction of a printing-friendly hole transport layer resulted in a PCE of 12.7% for the devices fabricated in air.