Perovskite Core-Shell Nanowire Transistors : Interfacial Transfer Doping and Surface Passivation

While halide perovskite electronics are rapidly developing, they are greatly limited by the inferior charge transport and poor stability. In this work, effective surface charge transfer doping of vapor-liquid-solid (VLS)-grown single-crystalline cesium lead bromide perovskite (CsPbBr3) nanowires (NWs) via molybdenum trioxide (MoO3) surface functionalization is achieved. Once fabricated into NW devices, due to the efficient interfacial charge transfer and reduced impurity scattering, a 15× increase in the field-effect hole mobility (μh) from 1.5 to 23.3 cm²/(V s) is accomplished after depositing the 10 nm thick MoO₃ shell. This enhanced mobility is already better than any mobility value reported for perovskite field-effect transistors (FETs) to date. The photodetection performance of these CsPbBr₃/MoO₃ core-shell NWs is also investigated to yield a superior responsivity (R) up to 2.36 × 10³ A/W and an external quantum efficiency (EQE) of over 5.48 × 105% toward the 532 nm regime. Importantly, the MoO₃ shell can provide excellent surface passivation to the CsPbBr₃ NW core that minimizes the diffusion of detrimental water and oxygen molecules, improving the air stability of CsPbBr₃/MoO₃ core-shell NW devices. All these findings evidently demonstrate the surface doping as an enabling technology to realize high-mobility and air-stable low-dimensional halide perovskite devices.