Investigations on inexpensive copper chalcogenide nanoparticles for efficiency enhancement in next generation solar cells

Abstract

The semiconducting quantum dots (QDs) which are tiny nanocrystals have gained tremendous attention as a versatile material to be employed in many emerging fields, such as quantum dots-based light emitting devices, solar cells, bioimaging, etc. The interesting physicochemical properties like bandgap energy tunability with varying size, high external quantum yield, and high extinction coefficient in visible region of solar spectrum are of great interest. Especially, the QD solar cells, which is an emerging and inexpensive technology, have turned as a potential candidate for the replacement of conventional solar cells and to confront the prevailing energy crisis. This thriving technology has reached remarkable world record efficiency of 16.7% till date with the tremendous efforts from the researchers all over the world. However, some limiting factors of the QDs based solar cells has to be addressed to promote these next generation solar cells as a promising alternative photovoltaic technology. The long-term stability, cost effectiveness, simple fabrication methods, usage of environmental benign materials are some of the necessary criteria for the large-scale production and commercialization of solar cells. In this thesis, the compelling research problems of the next generation QDs based solar cells have been addressed through the utilization of inexpensive copper chalcogenide nanomaterials. Owing to the multifunctional properties of the environmentally benign copper chalcogenides, they have turned as an attractive material for the replacement of expensive and hazardous materials in many fields. QDs sensitized solar cells (QDSSC) are suffering from the sustainable device performance and the stability issues which are the intimidating factors limit their practical application. The commonly used copper sulfide (CuxS) counter electrodes (CEs) were fabricated using high vacuum based thermal evaporation assisted processing technology. However, these CEs are expensive and unstablewith the prolonged exposure with poly