To reduce degradation, by the LID effect, of the conversion efficiency of photovoltaic cells made of crystalline silicon, one or more steps of controlled introduction of voids into the silicon are carried out by one or more steps chosen from among: siliciding, nitriding, ion implantation, laser irradiation, mechanical bending stress applied on one face of the silicon substrate, in combination with a temperature promoting the formation of voids in the substrate. These voids make it possible to reduce the level of interstitial oxygen by an effect of diffusion of VO complexes and precipitation of oxygen. The introduction of voids has the other effect of reducing the level of autointerstitials, and therefore of limiting the formation of interstitial boron. The phenomena of LID by activation of BiOi2 complexes are thus limited. This applies notably to photovoltaic cells based on monocrystalline or polycrystalline silicon having a high concentration of boron and oxygen.