When dilute charged particles are confined in a bounded domain, boundary effects are crucial for dynamics of particles which can be modeled by the Vlasov-Poisson-Boltzmann system. Considering a diffuse boundary condition, we construct a unique global-in-time solution in convex domains. This construction is based on L^2-L^\infty framework with a new weighted W^{1,p}-estimate of distribution functions and C^{2,\alpha}-estimate of self-consistent electric potentials. Furthermore we prove an exponential convergence of distribution functions toward a global Maxwellian.