Upconversion of SrWO4:Er3+/Yb3+: Improvement by Yb3+ codoping and temperature sensitivity for optical temperature sensors

- The successful codoping of Er2+ and Yb3+ ions into SrWO4.
- Enhancement of green emission intensities by the Yb3+ ions codoping.
- Obvious temperature-dependence of green emission on temperature.
- The sensitivity value of 0.01282 K−1 at 489 K for SrWO4:1%Er3+/6%Yb3+.