STUDIES ON HUMIDITY SENSING PROPERTIES OF AMMONIUM HEPTAMOLYBDATE TETRAHYDRATE (NH4)(6)[MO7O24]CENTER-DOT-4H(2)O

The material Ammonium heptamolybdate tetrahydrate has been shown to be an ionic conductor with t(ion) similar to 0.97. Its conductivity is s trongly humidity dependent dominated by surface ion transport. This ef fect has been utilized to develop a humidity sensor. A linear change o f similar to 2000 times in the resistance of the sensor with 'finger-t ype' electrodes has been observed when relative humidity changes from 10% to 95%. The response time has been found to be similar to 2 min wh en humidity changes from low to high R.H. values. The results have als o been compared with a conventional disc-type sensor having electrodes deposited on both sides.