Microwave Synthesized Monodisperse CdS Spheres of Different Size and Color for Solar Cell Applications

Carlos A Rodríguez-Castañeda,Claudia Martínez-Alonso,Paola M Moreno-Romero,Hailin Hu

doi:10.1155/2015/424635

Carlos A Rodríguez-Castañeda, Claudia Martínez-Alonso + Show 2 more

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https://doi.org/10.1155/2015/424635

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Abstract

Monodisperse CdS spheres of size of 40 to 140 nm were obtained by microwave heating from basic solutions. It is observed that larger CdS spheres were formed at lower solution pH (8.4–8.8) and smaller ones at higher solution pH (10.8–11.3). The color of CdS products changed with solution pH and reaction temperature; those synthesized at lower pH and temperature were of green-yellow color, whereas those formed at higher pH and temperature were of orange-yellow color. A good photovoltage was observed in CdS:poly(3-hexylthiophene) solar cells with spherical CdS particles. This is due to the good dispersion of CdS nanoparticles in P3HT solution that led to a large interface area between the organic and inorganic semiconductors. Higher photocurrent density was obtained in green-yellow CdS particles of lower defect density. The efficient microwave chemistry accelerated the hydrolysis of thiourea in pH lower than 9 and produced monodisperse spherical CdS nanoparticles suitable for solar cell applications.

Highlights

The increasing social conscience on the use of clean and renewable energy resources motivates the search on new materials, processes, or technologies for clean energy conversion systems
The cadmium sulfide (CdS) nanocrystals with size smaller than 10 nm were mostly synthesized through solution via using encapsulation agents, trioctylphosphine oxide (TOPO), for example, to avoid the agglomeration of the crystals [8]; without any encapsulation agent, the obtained CdS particles were of micron size and showed hydrophobic characteristic [9]
60 80 100 120 Diameter μm μm (c) pH 8.4, 150∘C, 10 min, 137.14 nm ± 27.92 nm (d) pH 10.8, 100∘C, 30 min, 51.68 nm ± 14.85 nm was a function of the initial solution pH (Figure 1(b) versus Figure 1(d)), the reaction temperature (Figure 1(a) versus Figure 1(c)), and time (Figure 1(a) versus Figure 1(b))

Summary

Introduction

The increasing social conscience on the use of clean and renewable energy resources motivates the search on new materials, processes, or technologies for clean energy conversion systems. Cadmium salt, sodium citrate, pH adjuster (KOH), and two different sources of sulfur, thioacetamide (TA) or TU, were used to synthesize CdS in a microwave oven with basic solutions [15] It reported that the CdS products from TA recipe were much more crystalline and showed morphology of hexagonal particles with random distribution of particle size. It is demonstrated that monodisperse spherical CdS nanoparticles with diameters from 40 to 140 nm could be obtained through a careful control of solution pH, reaction temperature, and time during the microwave assisted heating. Microwave heating was a simple and efficient method to obtain monodisperse inorganic semiconductor nanoparticles for solar cell applications

Experimental

Results and Discussion

Conclusions