Various antireflection thin films are often used to cover glass to increase solar cell Electrical parameters. In the recent years many efforts have been done to develop and improve of solar cell films with high Electrical output. One of the most important challenges of obtaining of high-Efficiency thin films of solar cells is creation an effective light trapping system. The new polymeric protecting materials are called polyhedral oligomeric silsesquioxanes (POSS) that can improve the solar cells properties. In the present work, firstly Tetraglycidyloxypropyl tetramethyl POSS was synthesized via sol-gel method and used to prepare TGTM POSS-silica nanocomposite, then it was applied on solar cell slides. The structural, morphological, thermal, optical and Electrical properties were investigated by TEM, FTIR, NMR, FE-SEM, TGA, UV-VIS spectroscopy and solar simulator. Evaluation of the obtained results showed that the Efficiency of solar cells was improved twice or more (50%) compared with that without POSS coating. The coatings transmittances were equal 100% that are ideal for solar cell films. The solar cells stability to solar light with POSS coating was also evaluated. The obtained results showed that the degradation of solar cell transmission.