Amplification of active sites and porosity for the adsorption of QDs via the induction of the rare-earth element la into TiO2 for enhanced photovoltaic effects in QDSSCs. (19th November 2020)

• Record Type: Journal Article
• Authors: Shwetharani, R.; Sushmitha, T.; Preethi, G. U.; Balakrishna, R. Geetha
• Is Part Of: New journal of chemistry. Volume 44:Number 46(2020)
• Page Start: 20441
• Page End: 20448
• Publication Date: 2020-11-19
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d0nj03718d
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Schematic representing preparation of TiO2 and La–TiO2, QDSSCs device development and mechanism of charge carrier's migration in device along with IV curve for La–TiO2 . Abstract : Quantum dot-sensitized solar cells (QDSSCs) have emerged as an attractive area of research, enabling the construction of efficient third-generation photoelectrochemical solar cells with a higher theoretical photon conversion efficiency of up to 44%. The power conversion efficiency ( η ) rates of several QDSSCs are lower than those of dye-sensitized solar cells, reaching a maximum of 13.4%; meanwhile, the major drawbacks of QDSSCs are their narrow absorption range and the recombination of charge carriers occurring at the QD- and TiO2 -electrolyte interfaces. Tailoring the band structure is an efficient pathway to facilitate charge carrier transportation, which in turn enhances light absorption and reduces charge carrier recombination. Doping/modifying the electron transport layer (ETL), namely TiO2, with rare earth elements has been proved to enhance the catalytic activity. Here, we report the investigation of incorporation of La 3+ into TiO2 to tailor its band structure and physical characteristics of ETL; this remarkably enhanced the photon conversion efficiency (PCE) of the La–TiO2 photoanode to 3.28%, with a charge transfer resistance of 452.21 Ohm, in contrast to the PCE of TiO2 (0.87%). The study indicates successful incorporation of La 3+, oxygen vacancies, efficient charge carrier separation, band gap reduction, favorable band gap alignment for effective electron transfer, a broad visible light absorption range, reduced particle size and enhanced surface area in the rare earth element-doped nanostructured titania. The obtained characteristics of the La-doped TiO2 were exploited as an ETL in QDSSCs to boost their photovoltaic performance.