Enhancement of Photothermal Conversion by TiN Nanoparticles-Embedded Black Paint and Applications in Solar Drying of Red Chilli

This work explores a new application of titanium nitride nanoparticles (TiN NPs) as efficient photothermal materials in enhancing the greenhouse effect. We demonstrate that a simple greenhouse using TiN NPs-embedded black paint boasts several advantages in solar drying technology, which are indicated by the drying of red chilli. In particular, the greenhouse using TiN NPs significantly improves the drying efficiency, which reduces the mass of red chilli by approximately four times and results in dried chilli with a moisture content of 10% within two days. In addition, by conducting long experiments in various environments, we found that the relative humidity can have a predominant role over the temperature in the solar drying of red chilli and observed that the re-adsorption of moisture can take place during the drying process, which prolongs the drying time and reduces the quality of the dried products.