Abstarct: An important reason for low efficiency of silicon solar cells is the mismatch between the incident photons energy and band gap energy of solar cell, photons with energy lower than band gap energy are not absorbed and for photons with energy higher than band gap energy, their excess energy is transformed into kinetic energy of the produced electron-hole pair and is wasted subsequently. UV spectrum is the part of the sun radiation which has high energy. The energy of this part of sunlight spectrum is more than silicon band gap energy, so this part of light is not absorbed completely by silicon solar cell and some of the energy of the incident photon is wasted in terms of heat and phonons. In this research we intended to change UV spectrum into another range of light spectrum that could be absorbed better by silicon solar cell and its energy be near to silicon band gap energy. Phosphorus is a material with photoluminescence property that absorbs UV spectrum of sunlight and emits visible and infrared light, that’s why we used phosphorus laxyers, so that deposited phosphorus on silicon solar cells surface using physical vapor deposition (PVD) method. Deposition was repeated several times for different thickness of phosphorus laxyer and after every deposition efficiency of the cell was measured, by comparing the efficiency after deposition and the efficiency before it, we found some increase in the efficiency of the cell. Thicker laxyers of phosphorus led into more increase in solar cells efficiency, by increasing thickness of laxyers, increasing in solar cell efficiency stopped in 200 nm laxyer thickness and the variation of efficiency was descending for laxyers thicker than 200 nm. absorption spectra of the phosphorus laxyers was measured before and after deposition and it was found that phosphorus absorbs some of the radiations in UV spectrum. luminescence spectra was measured and it was found that phosphorus has emission in range of visible and infrared light. X-Ray Diffraction (XRD) analysis was done for phosphorus laxyers and it was found that phosphorus laxyers have amorphous structure. SEM analysis was done for phosphorus laxyers and it was found that phosphorus laxyers are not conformal and phosphorus is aggregated in numerous points on the surface of silicon solar cell.