Interfacial Assembly of Ti₃ C₂ T_x /ZnIn₂ S₄ Heterojunction for High-Performance Photodetectors

Two-dimensional (2D) materials have emerged as prospective candidates for electronics and optoelectronics applications as they can be easily fabricated through liquid exfoliation and used to fabricate various structures by further subsequent processing methods in addition to their extraordinary and unique optoelectronic properties. Herein, the Ti₃ C₂ T_x /ZIS heterostructure with nanometer-thick Ti₃ C₂ T_x -MXene and ZnIn₂ S₄ (ZIS) films is fabricated by successive interfacial assembly of liquid exfoliated 2D MXene and ZnIn₂ S₄ nanoflakes. Benefiting from the superior light-harvesting capability and low dark current of ZnIn₂ S₄ , the limited absorbance, large scattering coefficient, and high dark current disadvantages of MXene are ameliorated. Meanwhile, the separation and transport of photogenerated carriers in ZnIn₂ S₄ are improved due to the excellent electrical conductivity of Ti₃ C₂ T_x nanoflakes. As a result, the as-prepared Ti₃ C₂ T_x /ZIS heterostructure photodetector has excellent optoelectronic characteristics in terms of a high responsivity of 1.04 mA W^-1 , a large specific detectivity up to 1 × 10¹¹  Jones, a huge on/off ratio at around 10⁵ , and an ultralow dark current at ≈10^-12  A. This work demonstrates a convenient method to construct heterostructured photodetectors by liquid exfoliated 2D nanoflakes, the as-fabricated Ti₃ C₂ T_x /ZIS heterostructured photodetectors show promising application potential for low-cost, reliable, and high-performance photodetectors.