Solar light absorber surface is probably one of the most important components in solar still that dictates the distillate yield. In this work, a systematic study is conducted to investigate the effect of particle size and concentration of titanium oxide (TiO₂) in black paint in increasing the solar still absorber surface temperature. The various available particle sizes, i.e., 20, 150, and 400 nm, are mixed in black paint with varying concentrations and are applied on the absorber plate. XRD is used for phase identification of as-received powders. UV-Vis spectroscopy is used to examine light absorption properties. Finally, extensive indoor testing (using an improvised solar simulator) and outdoor testing are conducted to optimize the concentration. An increase in surface temperature is observed with the introduction of TiO₂ nanoparticles in black paint. Furthermore, the increase in particle size leads to an increase in temperature. The highest surface temperatures of 104.86°C, 105.42°C, and 106.32°C are recorded for specimens with particles sizes 20 nm (at 15 wt% concentration), 150 nm (at 10 wt% concentration), and 400 nm (at 7 wt% concentration), respectively. Furthermore, the highest temperature of 69.69°C is recorded for TiO₂-400 nm specimens under outdoor conditions, which is 15.97% higher than that of the bare aluminum plate. The increase in surface temperature may be due to high UV absorption. Moreover, an increase in particle size leads to high light-scattering ability, further improving the light-harvesting ability.

太阳能光吸收器表面可能是太阳能蒸馏器中决定馏出物产量的最重要的组成部分之一。在这项工作中，系统研究了二氧化钛 (TiO ₂) 在黑色油漆中增加太阳能蒸馏器吸收器的表面温度。各种可用的粒径，即 20、150 和 400 nm，以不同的浓度混合在黑色涂料中，然后涂在吸收板上。XRD 用于原样粉末的相鉴定。紫外-可见光谱用于检查光吸收特性。最后，进行广泛的室内测试（使用临时太阳能模拟器）和室外测试以优化浓度。随着 TiO ₂的引入，观察到表面温度升高黑色涂料中的纳米颗粒。此外，颗粒尺寸的增加导致温度升高。对于粒径为 20 nm（浓度为 15 wt%）、150 nm（浓度为 10 wt%）和 400 nm（浓度为 7 wt% 浓度），分别。此外，在室外条件下，TiO ₂ -400 nm 样品的最高温度为 69.69°C ，比裸铝板的温度高 15.97%。表面温度的升高可能是由于高紫外线吸收造成的。此外，粒径的增加导致高光散射能力，进一步提高了光捕获能力。