4D nanoprinted sensor for facile organo-arsenic detection: A two-photon lithography-based approach

Engineered 3Dnanostructures have played a crucial role in the development of modern electronic devices. However, the demand for higher dimensional nanostructures have become a necessity for the development of superior next generation miniaturized devices. Traditional two-photon femtosecond laser-based fabrication techniques have enabled fabrication of 3D nanostructures. Carbon quantum dots have recently emerged as a new alternative for achieving subwavelength 3D optical lithography. Here, we report sensing of organo-arsenic(V) species at ppb levels using multimodal carbon quantum dots based 4D miniaturized ultrasensitive nanosensor and development of a device thereof using two-photon lithography. Manganese, nitrogen, and sulphur-doped carbon quantum dots have been used for development of this two-component, two-photon active functional resin for 3D printing of optically active 4D nanostructures. These have sub-wavelength resolved features, and are selectively sensitive to organo-arsenic species. The doped-carbon quantum dots initiate two-photon polymerization in the functional resin and induce emissive attributes to the polymerized nanostructures that impart selectivity towards dimethylarsinate ions (DAI) even at the ppb concentration levels. The miniaturized sensor strip shows a change in fluorescence of the nanostructures when subjected to the analyte. The emission intensities increases with increase in the concentration of DAI. The sensor can detect concentrations of the analyte as low as 1 ppb. This work opens new avenues to meet the demand for multi-dimensional nanostructures for development of superior next-generation of multifunctional miniaturized devices.