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Vitreous or vitreous humor is a complex transparent gel that fills the space between the lens and retina of an eye and acts as a transparent medium that allows light to pass through it to reach the photoreceptor layer (retina) of the eye. The vitreous humor is removed in ocular surgery (vitrectomy) for pathologies like retinal detachment, macular hole, diabetes-related vitreous hemorrhage detachment, and ocular trauma. Since the vitreous is not actively regenerated or replenished, there is a needfor a vitreous substitute to fill the vitreous cavity to provide a temporary or permanent tamponade to the retina following some vitreoretinal surgeries. An ideal vitreous substitute could probably be left inside the eye forever. The vitreous humor is transparent, biocompatible, viscoelastic and highly hydrophilic; polymeric hydrogels with these properties can be a potential candidate to be used as vitreous substitutes.To meet the tremendous demand for the vitreous substitute, many scientists all over the world have developed various kinds of vitreous substitutes or tamponade agent.Vitreous substitutes, whatsoever developed till date, are associated with several advantages and disadvantages, and there is no ideal vitreous substitute available till date. This review highlights the polymer-based vitreous substitutes developed so far, along with their advantages and limitations. The gas-based and oil-based substitutes have also been discussed but very briefly.

Earth abundant CZTS (Cu2ZnSnS4) absorber layers are promising for the development of cost-effective and large area photovoltaics; however, interfacial nonradiative recombination is a major obstruction to the pathways toward high performing CZTS devices. Elimination of interfacial recombination losses via interface engineering is paramount to obtain efficient CZTS solar cells. Herein, we report a systematic investigation of the influence of oxygen vacancies (OV) settled at the CZTS/TiO2 interface on the charge transfer rate in heterostructures. Modulation of OV by varying oxygen flow rate during TiO2 deposition was confirmed by x-ray photoelectron spectroscopy. Lower OV concentration shifted the conduction band offset from negative to positive at the CZTS/TiO2 heterojunction, which is essential for efficient charge transportation through the interface. Photoluminescence quenching of the CZTS/TiO2 heterojunction also showed a strong correlation between charge dynamics and OV at the interface. Finally, we found the fast decay response of photogenerated charge carriers for the CZTS/TiO2 device with lower OV strongly favors the suppression of carrier trapping at the interface. This work provides a critical insight into interface engineering in CZTS solar cells through regulating interfacial OV, particularly when an oxide electron transport layer is applied.

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A unique metal–semiconductor–metal (MSM) photodetector has been fabricated using Sn incorporation in Ga2O3 forming SnxGa1-xO nanostructures (Ns) with platinum (Pt) metal as contacts. The mixed nanostructures (MNs) has been attributed to an increment in the detection range of UV (254–302 nm) with ultra-low dark current, hence a potential device in the field of long range deep-UV detector. SnxGa1-xO Ns are deposited on c-plane sapphire using low-pressure chemical vapour deposition. From the x-ray diffraction (XRD) results, existence of both SnxGa1-xO and tetragonal SnO2 MNs are confirmed. The XRD peak shifts in SnxGa1-xO are attributed to the integration of Sn with Ga forming a SnxGa1-xO alloy with x to be ∼7.3% determined from the Vegard’s law. The field effect scanning eletron microscope images show the thick diameter wire-shaped nanostructures. The absorption spectra show a trace of two absorption edges corresponding to both SnxGa1-xO and SnO2 Ns. Photo to dark current ratio (PDCR) of the fabricated photodetector is large (103) at 2 V bias with fast fall time of 0.18 s. The detector reveals self-powered behaviour also with PDCR >104 at 0 V bias. The dark current is ultra-low (13 pA at 5 V) due to high barrier height of Pt and the UV detection range has been extended from 254–302 nm with a very small drop in PDCR owing to incorporation of Sn.