Enhancing the performance of PbS:Hg quantum dot - sensitized solar cells by controlling the surface charge of TiO2 electrode

Abstract

Colloidal quantum dots offer a number of advantages such as higher molar extinction coefficients, multiple exciton generation and tunable energy band gap due to the quantum confinement effect. They are providing a powerful platform for the development of several optoelectronic devices including solar cells, infrared detectors and light emitting diodes. Semiconductor quantum dot - sensitized solar cells have received more attention in recent years due to their cost - effectiveness as well as ease of fabrication. Recently, several types of quantum dots have been studied in quantum dot - sensitized solar cell applications such as CdS, CdSe, CdTe, CdSeTe, PbSe, PbS etc. In this work, TiO2 nanoporous layer has been sensitized with Hg - doped PbS quantum dots by successive ionic layer adsorption and reaction (SILAR) method. Effect of surface charge on TiO2 electrode has been studied by changing the amount of triethanolamine (TEA) in the cationic precursor solution during the SILAR process. A maximum efficiency of 4.25 % has been obtained with an open - circuit voltage of 626.1 mV and a short - circuit current density of 10.91 mA cm-2 corresponding to 0.8 M TEA in the cationic precursor solution.