In this proposal we intend to complete the characterization of the hydrogen impurity in solar cell materials Cu2ZnSnS4 (CZTS) and Cu(In,Ga)Se2 (CIGS), by using the positive muons as an analogue. In particular, we intend to characterize the diffusion behaviour above room temperature and look for possible trapping of muons in native defects (likely the acceptor copper vacancies, leading to its passivation). We also intend to characterize the acceptor configuration of the isolated hydrogen impurity by determining its hyperfine interaction, as well as its possible ionization energy.