  We investigate the room temperature electronic properties of MnTiO3
synthesised by different preparation conditions. For this purpose, we prepared
MnTiO3 under two different cooling rates, one is naturally cooled while the
other is quenched in liq.nitrogen. The samples were studied using optical
absorbance, photoemission spectroscopy and band structure calculations.We
observe significant changes in the structural parameters as a result of
quenching. Interestingly, in the parent compound, our combined core level,
valence band and optical absorbance studies show the evidence of Mn existing in
both 2+ and 3+ states. The fraction of Mn3+ ions has been found to increase on
quenching. The increase in the fraction of the Mn3+ ions has been manifested
(a) as slight enhancement in the intensity of the optical absorbance in the
visible region.There occurs persistent photo-resistance when the incident light
is terminated after shining; (b) in the behaviour of the features (close to
fermi level) in the valence band spectra. Hence, the combined analysis of the
core level, valence band and optical absorbance spectra suggest the charge
carriers are hole like which further leads to the increase in the electrical
conductivity of the quenched sample. The present results provide recipe to tune
the optical absorption in the visible range for its applications in optical
sensors, solar cell, etc.
