Single-molecule spectroscopy has become a powerful method for using organic fluorescent molecules in numerous applications. Along with sensing applications in biology and solid-state physics or a... Show moreSingle-molecule spectroscopy has become a powerful method for using organic fluorescent molecules in numerous applications. Along with sensing applications in biology and solid-state physics or a variety of applications in quantum information technology, molecules offer interesting possibilities for fundamental research. One of the very interesting areas is the study of charge transport and electric field sensing at the nanoscale. Developing molecular nanosensors for electric fields can not only help to fundamentally explore the motion of charges in conductors and semiconductors but can also lead to very sensitive and accurate instruments for quasi-static charge tracing or even single-electron charge detection. Such research could eventually lead to the construction of precise electric field sensors that can act as an interface between the quantum state of an electron and the outside word. We developed fluorescence molecular systems and electronic circuits with the aim of electric-field sensing and optical detection of one single electron. Show less