Hasselt University has developed a photoelectric method for the readout of solid-states spin qubits in diamond. Based on the detection of free charge carriers resulting from color centres ionization, this method involves transitions between different charge states of the same defect. The objective of this four year FWO project (2021 – 2025) is to exploit this particular property of the photoelectric readout to realize a hybrid spin-charge quantum system. The idea is to use the superposition of two charge states of a point defect in diamond as qubit. Since charge state transitions can be coupled to spin transitions, this system can be used for coupling the charge and spin degrees of freedom, thus forming a novel type of hybrid quantum system. The goals of the project include the prediction of the mechanism of charge state transitions by ab-initio calculations and the experimental demonstration of charge state superposition, on nitrogen-vacancy centres and potentially on other types of spin defects in diamond.