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We demonstrate the effect of surface passivation of cadmium selenide quantum dots (CdSe QDs) (∼5–7 nm) by tri-n-octylphosphene-oxide (TOPO) and oleic acid (OA) on the structural and optoelectronic properties of their respective polymer : CdSe composites by dispersing them in poly(2-methoxy-5(2-ethylhexyloxy)-1,4-phenylinevinylene) and poly(3-hexylthiophene) polymers. It has been found that OA passivated-QDs (∼7 nm), as compared with TOPO passivated CdSe QDs (∼5 nm), are of (i) high quality that provide better steric stability against coagulation, homogeneity and photostability to their respective polymer : CdSe composites, (ii) show low value of Stern–Volmer quenching constant (KSV) calculated from photoluminescence quenching measurements. These effects have been attributed to (i) CdSe(OA) (∼7 nm) particles having relatively smaller surface energies compared with CdSe(TOPO) (∼5 nm) particles thus showing lesser quenching capabilities (ii) dominance of respective processes of photoinduced Förster energy transfer between host polymer (donors) and guest CdSe nanocrystals (acceptors) in polymer : CdSe(OA) composites and charge transfer in polymer : CdSe(TOPO) composites.

Dye-sensitized solar cells (DSSCs) have become the subject matter of significant interest for the research and due to their urge in the field of energy conservation. The safe supply of energy is welfare of human life. However, as an unattainable power-energy conservation source, also depletion of fossil fuels is an unfortunate mandate and, definitely it is imminent. To encounter this critical issue of energy, non-conventional sources of energy have gained lots of attention, especially solar energy because it’s a device that converts light-energy directly to electrical-energy without harming the environment. DSSCs provides a reliable and a cheap alternative for different kinds of Photovoltaics. The spectacle realization of Dye-sensitized-solar-cell is typically relying on photosensitizer (Dye), electrolyte and metal oxide semiconductor. A natural dye has become most credible alternative for such expensive and rare inorganic/chemical sensitizers, due to its lower cost, easy fabrication, eco-friendly and abundance of raw material. Also, DSSC has easily implemented technology with significant efficiency. This review paper enlightens the emergence, operation/fabrication, components and development of DSSCs using natural photo-sensitizers and factors that affect the stability.