AdvisorsAlshareef, Husam N.
KAUST DepartmentPhysical Science and Engineering (PSE) Division
Embargo End Date2022-09-29
Permanent link to this recordhttp://hdl.handle.net/10754/672036
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Access RestrictionsAt the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation will become available to the public after the expiration of the embargo on 2022-09-29.
AbstractMetal-halide perovskites have attracted intense research endeavors because of their excellent optical and electronic properties. Different kinds of electronic and optoelectronic devices have been fabricated using perovskites. A feasible approach to utilize these properties in real device applications with improved performance and new functionalities is by fabricating heterostructures with extraneous materials. We have developed mixed-dimensional heterostructure systems using three-dimensional (3D) metal-halide perovskites and different types of different two-dimensional (2D) materials, including semimetal graphene, semiconducting phosphorus-doped graphitic-C3N4 sheets (PCN-S), and plasmonic Nb2CTx MXenes. First, selective growth of single-crystalline MAPbBr3 platelets on monolayer graphene by chemical vapor deposition (CVD) is achieved to prepare the MAPbBr3/graphene heterostructures. P-type doping from MAPbBr3 is observed in the monolayer graphene with a decreased work function of 272 meV under illumination. The photoresponse of the fabricated phototransistor heterostructure verifies the enhanced p-type character in graphene. Such kind of charge transfer can be used to improve device performance. Then, bulk-heterojunctions made of MAPbI3-xClx and PCN-S are prepared in solution. The matched band diagram and the midgap states in PCN-S present a convenient and efficient approach to reduce the dark current and increase the photocurrent of the as-fabricated photodetectors. As a result, the on/off ratio increases from 103 to 105, and the detectivity is up to 1013 Jones with an order of magnitude enhancement compared to the perovskite-only device. Last, plasmonic Nb2CTx MXenes and MAPbI3 heterostructures are prepared for photodiodes to broaden the detection band to near-infrared (NIR) lights. The use of the perovskite layer expanded the operation of the diode to the visible range while suppressing the dark current of the NIR-absorbing Nb2CTx layer. The fabricated photodiode reveals a detectivity of 0.25 A/W with a linear dynamic range of 96 dB in the visible region. In the NIR region, the device demonstrates an increased on/off ratio from less than 2 to near 103 and much faster response times of less than 30 ms. The improved performance is attributed to the passivation of the MAPbI3/Nb2CTx interface.
CitationLiu, Z. (2021). Halide Perovskite-2D Material Optoelectronic Devices. KAUST Research Repository. https://doi.org/10.25781/KAUST-9PY69