Ultrafast Ionizing Radiation Detection by p–n Junctions Made with Single Crystals of Solution-Processed Perovskite

Organometallic perovskites are candidates for low-dose ionizing radiation due to their large mobility-lifetime product, large radiation absorption coefficient, high stability at ambient temperature, and ability to crystallize from solution at low temperatures. However, multiple unstable and expansive organic layers are required to block injected charges from the applied voltage. Here, a radiation photodiode based on p–n junctions formed in the CH 3 NH 3 PbI 3 crystallization process without any other organic layers is reported. Through controlling the location of the dopant, selenium (Se), and its concentration inside CH 3 NH 3 PbI 3 single crystals, the valence band offset of the band alignment is measured as 0 to 0.45 eV. The photodiodes require only two gold electrodes deposited on opposite faces of the CH 3 NH 3 PbI 3 single crystals, and the sensitivity for 60 keV X-ray and 1.25 MeV gamma-ray from Cobalt-60 reached 21 µC mGy air cm −2 and 41 µC Gy air cm −2 , respectively. Experiments measured the ultrafast response time to be 3 µs.