Layer-by-Layer Assembly-Based Heterointerfaces for Modulating the Electronic Properties of Ti3C2Tx 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 Ti3C2Tx MXene electronic properties is the key challenge to fabricate functional nanoelectronic devices. Here, we demonstrate a solution-processable route to fabricate Ti3C2Tx 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 Ti3C2Tx 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 ≤ T < 100 K, contrary to the weak localized transport phenomenon in Ti3C2Tx MXene. The difference in charge transport mechanism is supported by distinct magnetoresistance (MR) of the Ti3C2Tx MXene (negative MR, -0.4%) and 3-LBL assembly (positive MR, 1.6%). Therefore, the modulated electrical transport and superior oxidation stability of the Ti3C2Tx MXene in the 3-LBL assembly have the potential to develop next-generation optoelectronic and memory devices.