Transformation of the Excited State and Photovoltaic Efficiency of CH 3 NH 3 PbI 3 Perovskite upon Controlled Exposure to Humidified Air

Humidity has been an important factor, in both negative and positive ways, in the development of perovskite solar cells and will prove critical in the push to commercialize this exciting new photovoltaic technology. The interaction between CH(3)NH(3)PbI(3) and H(2)O vapor is investigated by characterizing the ground-state and excited-state optical absorption properties and probing morphology and crystal structure. These undertakings reveal that H(2)O exposure does not simply cause CH(3)NH(3)PbI(3) to revert to PbI(2). It is shown that, in the dark, H(2)O is able to complex with the perovskite, forming a hydrate product similar to (CH(3)NH(3))(4)PbI(6)·2H(2)O. This causes a decrease in absorption across the…

• BE
  Basic Energy Sciences

  Award: DE-FC02-04ER15533
• NR
  National Renewable Energy Laboratory