Tuning the d_xy Orbital Energy Level in 2D Cobalt‐Organic‐Framework via in‐Plane Conjugated Phthalocyanine for Self‐Powered Sensing

Abstract Precisely regulating the d orbital energy level of the transition metal center in the 2D conductive metal‐organic framework (2D cMOF) is critical for determining electrons transfer dynamics and enhancing sensing performances. Herein, this is demonstrated that a 2D cobalt‐MOF, decorated with in‐plane π conjugated phthalocyanine (Pc), acts as a highly electrically conductive nanofiller in a cellulose‐based hydrogel, facilitating the creation of an ultrasensitive self‐powered sensing system. The strong conjugation between the π‐orbital of Pc and the d‐orbital of MOF nanosheets raises the d_xy orbital energy level, promoting electrons delocalization. As a result, the optimized 2D MOF@Pc‐based conductive hydrogel achieved the highest electrical conductivity of 78 S m⁻¹ due to enhanced electron transfer kinetics. Moreover, as a key component in a triboelectric nanogenerator, supercapacitors, and sensor module, the overall performance of the assembled self‐powered sensing micro‐system is reinforced, yielding a 75% improvement in sensitivity. The coordination effect between Pc, MOF, and the biopolymers matrix also endowed the hydrogel with outstanding anti‐swelling capacity. Additionally, the wearable smart sensor successfully demonstrated its ability to track physiological data and transmit information in underwater. This work presents a progressive strategy for addressing the intrinsic low conductivity of 2D cMOF nanosheets in the sensing field.