The question you asked should be divided into specified categories and conditions. If found under the same natural field conditions: Polycrystalline is approximately 12% to 15%. Single crystal 14%-17%. The difference in amorphous silicon is relatively large, some are higher and some are lower.
In the most ideal situation, battery purity and integration should be optimal, reaching 25% in the laboratory. It can reach 20% outdoors. In space, it can reach 37%.