Study on preparation and properties of boron-gallium co-doped multicrystalline ingots

•The optimal gallium-doped ratio of multicrystalline ingots is between 20 and 25%.•The lifetime and efficiency both decreased with increase of gallium ratio beyond 25%.•The concentration of gallium is the primary factor that affects the LID of ingots.•The concentration of Cu and Fe can also affect the LID of ingots toacertainextent.