Radiation Chemistry-Based Molecule Grafting: A Fast Track to Diamond-Based Hybrid Sensors

Nitrogen vacancy (NV) center-containing fluorescent nanodiamonds are promising quantum sensors for several industrial, medical, and biotechnological applications. A key factor in their applicability is their surface functionality, which can be modified in many ways. In this paper, we present primary results on a new approach for the synthesis of luminescent dye nanodiamond conjugates through an electron beam-induced radiation-chemical modification of nanodiamonds. This method involves grafting of fluorene and 9,10-dimethylanthracence. The successful modification is characterized using spectroscopic, microscopic, and mass spectrometric methods. The obtained results show that the radiation-chemical modification of nanodiamonds is fast and efficient and leads to a stable bonding of the molecule on the particle surface. For the 9,10-dimethylanthracence conjugate, a wavelength-selective excitation of the fluorescent dye and NV center inside the nanodiamond could be demonstrated. The fast radiation chemistry-based synthesis of new nanodiamond conjugates could be used to manufacture multiparameter hybrid sensor particles, with a high impact on sensor technology, medicine, and biotechnology.