The toxicity and stability risk of perovskite structured materials have raised concerns in respective to utilization as a solar energy conversion material. The most common perovskite structured material is lead (Pb)-based, which is an element that is knowingly toxic to humans and the environment. Although the stability issue has been well allayed with several optimizations, the ruinous Pb remains a future challenge for perovskite solar cells. Compositional and structural derivatives of the perovskite family, specifically vacancy-ordered double halide perovskites (DHPs), have attracted the attention of researchers in terms of efficiency and toxicity issues subjugation. Although tin (Sn)-based vacancyordered DHPs have been widely explored, the intrinsic property conduces low performance output. Titanium (Ti) is a potential substituting candidate of Sn in a vacancy-ordered DHPs structure. It is an environment-friendly element ideal for sustainable perovskite structured compositions. Rudimentary studies of Ti-based vacancy-ordered DHPs emphasized its potential development as an eco-friendly and stable solar cell. In promoting the development of Ti-based vacancy-ordered DHPs as potential absorbers, we summarized herein the recent progress of experimental and theoretical studies of this perovskite material.

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There has been a large amount of work being conducted on the thermo-dynamics of the Direct Contact Condensation (DCC), however, not much attention was given to the phenomena particularly active near the steam’s nozzle exit. A transparent rectangular upright duct of 4 ft high, was built with a supersonic nozzle positioned at the bottom of the channel to characterize flow behavior near the steam nozzle’s exit. Particle image velocimetry (PIV) was applied to draw information on the steam’s jet penetration into the water as well as the entrainment and mixing between the two phases under the steam’s inlet pressure ranging from 1.5 – 3.0 bars. PIV normalized contour measurements depicted not appreciable changes in the radial velocity of the jet. Whereas, in the core region of the jet, the change in the jet’s velocity was not much till Y/De ~ 4.3 and the vertical velocity of the jet decreased slowly till Y/De ~ 8. The jet’s normalized upward velocity attained an optimized value between Y/De ~ 8 and Y/De ~ 9.8. With varying pressures, 1.5 bars to 3.0 bars, the jet expanded radially in water. It was also found in the near nozzle exit region, the shear layer’s thickness remained within 0.2 – 0.5 De over the 1.5 – 3.0 bars pressure. Probability Density Function (PDF) analysis of Reynolds shear and normal stresses confirmed the existence of the velocity fluctuations across the shear layer, owing to the large eddies across the steam-water interface.