Defect Passivation and Fabrication of Stable Large-Area (2.0 cm2) Perovskite Solar Cells with Cost-Effective Metal Contacts

Improving the quality of the perovskite thin film is essential for fabricating highly efficient perovskite solar cells (PSCs). However, the widely used mixed cation RbCsMAFAPb­(IBr)3 perovskite absorber layer contains many defects, which work as charge recombination centers, decreasing the device’s performance. Herein, we introduce phenethylammonium chloride (PEACl), an additive in the perovskite precursor solution, to reduce surface defects and nonradiative recombination, strongly influencing the charge-transfer dynamics and stability of the small- and large-area PSCs. With the inclusion of the PEACl additive, the fabricated “champion” device exhibits an excellent power conversion efficiency (PCE) of 17.40%, with a J SC of 24.27 mA/cm2, V OC of 0.95 V, and fill factor (FF) of 75.42% with PTAA hole-transporting layer (HTL), in combination with silver (Ag) metal contact electrode over 0.25 cm2 active area. When the active area was scaled up to 2.0 cm2, the device exhibited a PCE of 10.30%, with a V OC of 1.0 V, J SC of 16.75 mA/cm2, and FF of 61.19%. The fabricated PSCs with an active area of 0.25 and 2.0 cm2 retained 71 and 73% of their PCE after 1000 h of storage in the ambient conditions without encapsulation. PTAA HTL and Ag electrode combination for the PSCs with PEACl additive passivation exhibits a quick, simple, and low-cost technique to fabricate high-efficiency devices.