Ultrasensitive 1D field-effect phototransistor: CH$_3$NH$_3$PbI$_3$ nanowire sensitized individual carbon nanotube

摘要

Field-effect phototransistors were fabricated based on individual carbonnanotubes (CNTs) sensitized by CH$_3$NH$_3$PbI$_3$ nanowires (MAPbI$_3$NW).These devices represent light responsivities of R=7.7x10$^5$ A/W atlow-lighting conditions in the nWmm$^{-2}$ range, unprecedented among CNT-basedphoto detectors. At high incident power (~1 mWmm$^{-2}$), light soaking resultsin a negative photocurrent, the device turns insulating. We interpret thephenomenon as a result of efficient electron-hole separation and chargetransfer of holes from the perovskite to the carbon nanotube, which improvesconductance by increasing the number of carriers, but leaves electrons behind.At high illumination intensity the random electrostatic potential of thesequench the mobility in the nanotube. The single CNT device geometry allows thelocal study of the MAPbI$_3$NW/CNT interface for metallic and semiconductingCNTs separately. Infrared and Raman spectroscopy studies ofCNT-CH$_3$NH$_3$PbI$_3$ composites revealed that photo-doping takes place atthe interface.