Cross-sections of a hole-conductor-free CH 3 NH 3 PbI 3 perovskite solar cell were characterized with Kelvin probe force microscopy. A depletion region width of about 45â €...nm was determined from the measured potential profiles at the interface between CH 3 NH 3 PbI 3 and nanocrystalline TiO 2, whereas a negligible depletion was measured at the CH 3 NH 3 PbI 3 /Al 2 O 3 interface. A complete solar cell can be realized with the CH 3 NH 3 PbI 3 that functions both as light harvester and hole conductor in combination with a metal oxide. The band diagrams were estimated from the measured potential profile at the interfaces, and are critical findings for a better understanding and further improvement of perovskite based solar cells.
Bibliographical noteFunding Information:
We would like to thank the Israel Alternative Energy Foundation (I-SAEF) that financed this research, the Ministry of Industry Trade and Labor Office of the Chief Scientist Kamin project No.50303, and the Tashtiot project of the Office of the Chief Scientist.