In this paper, we investigate the effect of thermal annealing on nonradiative recombination parameters ofGaAsPN materials used for intermediate band solar cells. This study is performed thanks to photothermaldeflection technique PTD. Indeed, nonradiative lifetime, electronics diffusivity, surface and interface recombination,are extracted through a good fit between theoretical and experimental amplitude and phase of PTDsignal. Then, the effects of annealing temperature on charge transport were analyzed and discussed. As animportant result for solar cells improvement, we have found that hole diffusion length and mobility increasesrespectively from 13.8 to 19 (+/-2.5%) μm and from 112 (+/-4.9%) to 153 (+/-3.5%) cm2/V⋅s for GaAsPN as grown tothat annealed at 800 °C.