Copper yttrium selenide: A potential photovoltaic absorption material for solar cells

Significance Statement

The unique structural and photoelectric characteristics of copper based ternary and quaternary semiconductor compounds favors their wide applicability as absorption materials in thin film solar cells. Most research on this type of materials has focused mainly on group IIIA compounds of the periodic table. The polycrystalline compound Cu(In,Ga)Se2 has yielded the highest conversion efficiency to date. However, indium and gallium are expensive due to their scarcity, thereby increasing the cost of production of solar cells and limiting their wide-scale applicability. Researchers have thus been coerced to seek for alternatives where the advantages of doping semiconductors such as copper yttrium selenide with rare earth elements has attracted their attention and presented an alternative. Yttrium is cheaper, more abundant and less toxic than both indium and gallium. So far, no report on the optoelectronic properties of the Copper yttrium selenide as an absorption material for solar cells has been presented.

 A team of researchers led by Professor Ruixin Ma at the University of Science and Technology in China proposed a study on the optoelectronic properties of copper yttrium selenide. They successfully synthesized the Copper yttrium selenide using self-propagating high temperature synthesis technique and measure its optoelectronic properties. Their work is now published in Materials and Design.

First, the research team synthesized the novel photovoltaic material: copper yttrium selenide, using a self-propagating high temperature synthesis method. The process had three stages and the optimum temperature of the copper yttrium selenide synthesis was 1016.2°C. The authors of this paper then characterized the crystalline morphology of the copper yttrium selenide using X-ray diffraction and field emission scanning electron microscopy. They then estimated the band gap of the copper yttrium selenide material based on the ultraviolet-visible spectroscopy spectrum of the material. A thin film of the copper yttrium selenide was prepared and used to determine the current-voltage properties.

The team noticed that the newly synthesized copper yttrium selenide exhibited outstanding absorption property in the visible light region. They also recorded the band gap to be 1.53 eV which is close to the optimal value for use in the solar cells. Most important of all, the copper yttrium selenide film used exhibited an exceptional photo-electron responsive behavior of a Ilight/ Idark  ratio of 2.81. This showed that the copper yttrium selenide was very suitable for use as an absorption material of thin film solar cells.

The work described herein presents and illustrates the novel copper yttrium selenide as a promising candidate for use as an absorption material in low cost and mass production fabrication of thin film solar cells. The success of copper yttrium selenide lengthens the list of available species of materials for use in low cost solar cells. 

Reference

Shina Li, Ruixin Ma, Xiaoyong Zhang, Xiang Li, Weishuang Zhao, Hongmin Zhu. Copper yttrium selenide: A potential photovoltaic absorption material for solar cellsMaterials and Design, volume 118 (2017) pages 163–167.

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