Fabrication, Characterization, and Optimization of CdS and CdSe Quantum Dot-Sensitized Solar Cells with Quantum Dots Prepared by Successive Ionic Layer Adsorption and Reaction

H K Jun,M A Careem,A K Arof

doi:10.1155/2014/939423

Abstract

CdS and CdSe quantum dot-sensitized solar cells (QDSSCs) were used for the study of determining the optimum preparation parameters that could yield the best solar cell performance. The quantum dots (QDs) were coated on the surface of mesoporous TiO2layer deposited on FTO substrate using the successive ionic layer adsorption and reaction (SILAR) method. In this method the QDs are allowed to grow on TiO2by dipping the TiO2electrode successively in two different solutions for predetermined times. This method allows the fabrication of QDs in a facile way. Three preparation parameters that control the QD fabrication were investigated: concentration of precursor solutions, number of dipping cycles (SILAR cycles), and dipping time in each solution. CdS based QDSSC showed optimum performance when the QDs were prepared from precursor solutions having the concentration of 0.10 M using 4 dipping cycles with the dipping time of 5 minutes in each solution. For CdSe QDSSC, the optimum performance was achieved with QDs prepared from 0.03 M precursor solutions using 7 dipping cycles with 30 s dipping time in each solution. The QDs deposited on TiO2surface were characterized using UV-vis absorption spectroscopy, FESEM, and TEM imaging.

Highlights

The rise of carbon footprint has triggered people to think of ways to reduce the carbon emission
For the preparation of CdSe quantum dots (QDs) 0.03 M precursor solutions were used and a dipping time of 30 s was set for each dipping
Based on the results reported above, the most efficient CdS quantum dot-sensitized solar cells (QDSSCs) can be fabricated with QDs prepared from precursor concentration of 0.10 M using 4 successive ionic layer adsorption and reaction (SILAR) dipping cycles with a 5 min dipping time in each solution

Summary

Introduction

The rise of carbon footprint has triggered people to think of ways to reduce the carbon emission. Dye-sensitized solar cells (DSSCs) have been deeply investigated as a possible low cost alternative to the costly conventional solar cells [1,2,3] This was followed by the introduction of semiconductor quantum dots (QDs) as an alternative light absorber to replace the widely used expensive inorganic dyes in DSSCs [4]. The SILAR technique has been widely used to fabricate CdS QDs due to its simplicity [8, 17] It has the advantage of depositing QDs with controlled size and volume by varying the parameters such as precursor concentration (cationic and anionic solution), number of dipping cycles, and dipping time. The processing parameters to fabricate QDs were varied in order to obtain solar cell performance of optimum efficiency. Optimum parameter settings for the synthesis of CdS and CdSe QDs by SILAR method are anticipated

Experimental

Results and Discussion

Determining the Optimum Concentration for Precursor Solutions

Conclusions