Dye-sensitized solar cells (DSSCs) are promising photovoltaic technology with diverse indoor and outdoor applications. DSSCs can be integrated with curtains and glasses to power various devices, including wireless sensors, computer network peripherals, internet-of-things (IoT) devices, and wearable electronics. DSSCs have the potential to become the future source of energy. However, their efficiency, stability, and industrial production still need to be scaled up. The present review encompasses these elements and the various changes that have occurred inside the DSSC over the last few years, including device structure, TiO2 photoelectrode, novel electrolytes, new organic photosensitizers, efficient catalyst materials, and encapsulation strategies for sealing DSSC devices. We further discuss how the performance of each functional component of a DSSC has been enhanced as a result of the introduction of novel materials and manufacturing processes. In addition, we also briefly cover p-DSSCs and tandem DSSCs. Finally, the prospect of highly efficient and stable DSSCs is highlighted.

A comparative study of the second harmonic generation in ZnO micro particles and nanorods has been experimentally studied by Kurtz technique using nanosecond pulsed Nd:YAG laser. The results have been theoretically explained by taking into account the quadrupole moment as well as surface nonlinearity. It was observed that the nanorods yield polarized second harmonic signal while the second harmonic signal obtained from the micro particles was unpolarized.

Para-nitroaniline(p-NA)-dimethyl formamide (DMF) adduct has been synthesized chemically. The formation of adduct is confirmed via UV, FTIR, CHN analyses and other techniques. The adduct formation takes place due to dipolar interaction and hydrogen bonding. The parent polar molecules, viz. p-NA and DMF, crystallize in symmetric forms and do not exhibit optical second harmonic generation (SHG). The adduct has been found to exhibit a considerable SHG efficiency and hence this confirms that the adduct crystallizes in a noncentrosymmetric form. These observations suggest a Λ-shaped structure of the molecule, which is further established theoretically via geometry optimization.

In epoxy based polymeric nonlinear optical (NLO) materials, the nonlinear optically active moiety forms crosslink between polymer chains. Some of the important moieties include 4, 4 diamino diphenyl sulfone (DADS). We have examined second harmonic generation (SHG) in DADS and have compared it with 4, 4 diamino diphenyl methane (DADM). The geometry optimization suggests that both molecules have Λ-shaped structure. The theoretical calculations as well as experimental observations of SHG in both the molecules suggest the suitability of DADS over DADM for making polymeric NLO materials.

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