Fermion tunneling of charged particles from a non-static black hole in de Sitter space

Introducing a new coordinate system and choosing a set ofappropriate matrices γ^μ , this paper attempts toinvestigate the fermion tunneling of charged particles across theevent horizon from the Vaidya--Bonner de Sitter black hole. The resultshows that the tunneling rate of the non-static black hole isrelated not only to the change of Bekenstein--Hawking entropy butalso to the integral of the changing horizon, which violatesunitary theory and is different from the stationary case.