Strain-modulated ultrafine bimetallic Au/Cu co-doped MoS₂ nanoflower for highly selective detection of dopamine

Strain modulation in two-dimensional transition metal dichalcogenides (TMDs) has emerged as an effective strategy for tailoring their electronic structure and catalytic activity. Herein, a strain-modulated ultrafine bimetallic Au/Cu co-doped MoS₂ nanoflower (Au/Cu/MoS₂) was synthesized through a facile hydrothermal approach followed by solution-phase crystal growth for highly specific detection of dopamine (DA). A localized lattice strain is induced upon co-doping with Au and Cu, thereby creating numerous defect sites that significantly enhance accelerated charge transfer and superior catalytic efficiency. The synergistic interaction between Au, Cu, and MoS₂ reduces the energy barrier for DA oxidation, thereby enhancing electrochemical conductivity and accelerating electron transfer kinetics. Notably, the sensor exhibited a remarkable sensitivity and selectivity with a detection limit down to 0.01 μM and a diffusion-controlled oxidation mechanism. The exceptional selectivity arises from the negative surface potential of MoS₂ and the positively charged DA molecules under physiological pH, combined with abundant, energetically favorable Au-Cu catalytic sites. This study pioneers an advanced surface modification strategy that provides both high sensitivity and superior selectivity, paving the way for real-time neurotransmitter monitoring and expanding its potential in other cutting-edge analytical domains.