Strong green upconversion emission from Er3+-Yb3+ co-doped KCaBO3 phosphor

► Single phase monoclinic KCaBO3:Er3+-Yb3+ phosphors were synthesized. ► Strong green upconversion emission is successfully demonstrated. ► The increase in green emission upon Yb3+ increase is due to good crystallinity. ► Our results suggest a potential green phosphor for applications.