ZnO nanoparticles have gained considerable interest lately due to their remarkable optical and electrical properties, which enable them to have the potential to be the next generation of transparent semiconductors. However, interactions with atmospheric water and surface carbonates limited and seriously threatened device stability and dependability. The UV photoconductivity of the ZnO NP films is heavily influenced by oxygen adsorption and organic species in the ambient air. The stability of the ZnO photodetector prepared, annealed, and tested in a nitrogen atmosphere was improved in terms of current magnitude and sustaining photocurrent cycles. ZnO NPs films processed in the air show considerable change in surface composition compared to nitrogen indicated by surface organic complexes. In an oxidized manufacturing environment, the compounds above were effectively eliminated while partly degraded in nitrogen. We find that the ZnO NPs surface is highly reactive with ambient CO2, generating surface carbonates groups that promote electrically active surface states.