We applied the deactivation treatments to p-type single crystalline silicon solar cells for deactivating the recombination-active boron-oxygen complex. The methods we used include thermal annealing treatment, capacitively couple plasma (CCP) treatment, and plasma immersion ion implantation (PIII) treatment. The results showed that all the deactivation treatments were working and the energy transfer efficiency (Eff) was thereby increased by more than 1% absolute compared to the degraded state base on the increasing of the open-circular voltage (Voc) and short-current density (Jsc). The CCP deactivated treatment got better efficiencies than PIII treatment because the PIII treatment damaged the surface of solar cells. After the forming gas treatment, the samples could be improved to close to the PIII samples due to the surface damage repairing. However, the increased efficiency could not be kept and would be degraded again after illumination.