This study demonstrates significant visible light photo-detection capability of pristine ZnO nanostructure thin films possessing substantially high percentage of oxygen vacancies and zinc interstitials , introduced by simple tuning of economical solution method. The demonstrated visible light photo-detection capability, in addition to the inherent UV light detection ability of ZnO, shows great dependency of and with the nanostructure morphology. The dependency was evaluated by analyzing the presence/percentage of and using photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) measurements. Morphologies of ZnO viz. nanoparticles (NPs), nanosheets (NSs) and nanoflowers (NFs), as a result of tuning of synthesis method contended different concentrations of defects, demonstrated different photo-detection capabilities in the form of a thin film photodetector. The photo-detection capability was investigated under different light excitations (UV; 380~420 nm, white ; λ > 420 nm and green; 490~570 nm). The as fabricated NSs photodetector possessing comparatively intermediate percentage of ~ 47.7% and ~ 13.8% exhibited superior performance than that of NPs and NFs photodetectors, and ever reported photodetectors fabricated by using pristine ZnO nanostructures in thin film architecture. The adopted low cost and simplest approach makes the pristine ZnO-NSs applicable for wide-wavelength applications in optoelectronic devices.

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Nanosheets, nanoparticles, and microstructures of ZnO were synthesized via a wet chemical method. ZnO films with a thickness of 44-46 µm were fabricated by spray coating, and these have been investigated for their potential use in turbid lens applications. A morphologydependent comparative study of the transmittance of ZnO turbid films was conducted. Furthermore, these ZnO turbid films were used to enhance the numerical aperture (NA) of a Nikon objective lens. The variation in NA with different morphologies was explained using size-dependent scattering by the fabricated films. A maximum NA of around 1.971 of the objective lens with a turbid film of ZnO nanosheets was achieved.