PHOTOELECTRIC CHARACTERIZATION OF DYE SENSITIZED SOLAR CELL (DSSCS) BASED ON NITROGEN DOPED CARBON QUANTUM DOT (CQDT) AND NATURAL PIGMENT EXTRACTED FROM ROSELLE HYBISCUS SABDARIFA

Abstract

Citric acid, Ammonia and distilled water were used to synthesized Nitrogen doped carbon quantum dot (CQDT) and natural pigment was extracted from Roselle Hybiscus Sabdarifa flower. These sensitizers were used to fabricate monolithic dye sensitized solar cells, using Doctor Blade technique. Three samples of DSSCs were fabricated with CQDT, Hybiscus Sabdarifa dye and Hybiscus Sabdarifa +CQDT. These fabricated cells were characterized and the optical properties of the cells fabricated shows that the maximum absorbance of CQDT, hybiscus sabdarifa and hybiscus sabdarifa + CQDT was 1.75 %, 2.38 % and 2.17 % respectively. Moreso, the bandgap energy of the CQDT is 2.25 eV while hybiscus sabdarifa and hybiscus sabdarifa + CQDT is 1.88 eV and 1.92 eV respectively. The X-ray diffraction spectrum results reveals that the synthesized cells were polycrystalline in nature. The SEM
images further exhibit a nanograins, that is spread throughout the substrate surface which show a stacked like agglomeration due to glass substrate used for the synthesis. The average crystallite size obtained was about 1 to 9 nm from the XRD data. The photoelectrical properties of the CQDT, hybiscus sabdarifa and hybiscus sabdarifa + CQDT revealed that the conversion efficiency was 4.17 %, 2.63 % and 1.17% respectively. This shows that the dye adhere well with the CQDT material thereby creating space for photovoltaic activities.