One sensor pixel includes amplifying transistor, coupled between first bias line and data line; switch transistor, operated by control line and coupled between data line and gate of amplifying transistor; storage capacitor, coupled to second bias line; and sensor being coupled to gate of amplifying transistor. Another sensor pixel includes first amplifying transistor coupled between first bias line and data line; second amplifying transistor being coupled between second bias line and data line; switch transistor being operated by control line and being coupled between data line and gates of first and second amplifying transistors; storage capacitor coupled to gates of first and second amplifying transistors; and sensor coupled to gates of first and second amplifying transistors. Trap-assisted absorption, variable capacitor described for sensor pixels, and also biasing to reduce flicker and aging, and to compensate for aging, described for sensor pixels.