Layer-by-Layer Assembly-Based Heterointerfaces for Modulating the Electronic Properties of TiCT MXene.

Two-dimensional (2D) transition-metal carbides (MXenes) are emerging as promising materials for a wide range of applications owing to their intriguing electrical, optical, and optoelectronic properties. However, the modulation of metallic TiCT MXene electronic properties is the key challenge to fabricate functional nanoelectronic devices. Here, we demonstrate a solution-processable route to fabricate TiCT MXene/CuI nanoparticle heterointerfaces by employing a layer-by-layer assembly process. The charge transfer at the heterointerfacial assembly is monitored qualitatively from the quenched photoluminescence emission of CuI. The stable electrical conductivity and consistent Raman spectra of the 3-LBL assembly (three sequential stacks of CuI/MXene) signify the oxidation stability of TiCT thin films even after exposure to the ambient environment for 2 months. Furthermore, the 3-LBL assembly exhibited a three-dimensional (3D) variable-range hopping-based electrical conduction in the temperature range 2 ≤ < 100 K, contrary to the weak localized transport phenomenon in TiCT MXene. The difference in charge transport mechanism is supported by distinct magnetoresistance (MR) of the TiCT MXene (negative MR, -0.4%) and 3-LBL assembly (positive MR, 1.6%). Therefore, the modulated electrical transport and superior oxidation stability of the TiCT MXene in the 3-LBL assembly have the potential to develop next-generation optoelectronic and memory devices.