And good news for you is that BIOS file is already built inside PS3Mobi so you don't have to download it separately from web.
Shortly, BIOS (Basic Input/Output System) is a log file (manual) of codes which tells your device how to run certain console games correctly. In other words, this makes your device (smartphone/PC) to act like a real PS3 console while running its games. The application is coded in C & C++ languages with caching/recompilation method which achieves effect of emulating CPU of device you use and make it function like PS3's one does. Welcome abroad players! This is official website of PS3Mobi - No.1 emulator for Sony PlayStation 3 console built primarily for Android and iOS mobile operating systems, and later we decided to make it supported for desktop computers as well (with Windows and Mac OS).