This report studies the influence of alkali elements (Na, K) to morphological, structural and optoelectronic properties of CIGS ceramic tile solar cell. Several ceramic enamels with altered chemical composition in terms of amount of alkali elements have been tested and compared. The influences of alkali type, its quantity and transfer mechanism have been investigated. The solar cell device has been assembled and characterized. The achieved results indicate that alkali elements (Na and K combination) modified the surface roughness and its diffusion from the enamel toward the absorber affect to the structural and final optoelectronic properties of the device. The alkali doping improve the Ga incorporation in the crystal lattice and an increasing in open circuit voltage (Voc) values, fill factor (FF) and the device efficiency. Optimal alkali quantities have been also determined. The best conversion efficiency is achieved for the cell with 4% wt Na 2 O and 3.2 % wt K 2 O (Eff. = 3,5 %), which presents an improvement of 30 % in efficiency relative to the standard (STD) solar cell sample chosen for comparative purposes.

In this work the use of porcelain stoneware tiles as alternative substrates for CIGS thin film solar cells for the development of specific applications as those related to building integration (BIPV, BAPV) are reported. Two types of porcelain stoneware have been compared: the conventional tile (STD) and the ecological tile (ECO). The ECO ceramic paste formulation has been designed adding industrial wastes (recycled glass, sludges and chamote). Chemical, technological and functional properties of the paste have been performed. The CIGS absorber has been synthesized by an easy and low-cost way of preparation using co-precipitation method. The solar cell device has been completed and fully characterized.The achieved results indicate better performances for ECO paste compared to the STD, stated in improved mechanical resistance, thickness and morphology. It is demonstrated 2 that both tiles are suitable for solar cell applications, but ECO substrate developed higher energy conversion efficiency of 1.3 %.

No abstract

Title: Preparation of Cu(In,Ga)Se2 photovoltaic absorbers by an aqueous metal selenite coprecipitation route Abstract: In this paper, we report a novel and simple solution-based approach for the fabrication of chalcopyrite Cu(In,Ga)Se2 thin film solar cells. A novel aqueous co-precipitation method based on metal selenites, M2(SeO3)x (M= Cu, In, Ga) precursors, was investigated. The resulting powder, dispersed in a binder to form an ink, was coated on a substrate by doctor blade technique. A soft annealing treatment enabled the reduction into the corresponding metal selenides leading after rapid thermal processing (RTP) to crystalline chalcopyrite absorber. The obtained layer provides good compositional control and adequate morphology for solar cell applications. Doctor blade printing in atmospheric environment offers an opportunity for direct application of the absorber material at largescale. The water-based synthesis is a sustainable and simple procedure, and together with doctor blade printing, provides a potential cost-effective advantage over conventional fabrication processes (vacuum-based deposition techniques).The short circuit current (Jsc), open circuit voltage (Voc), fill factor (FF), and total area power conversion efficiency (Eff.) of the device are 26 mA/cm2, 450 mV, 62%, and 7.2 %, respectively. The effective band gap of 1.12 eV confirmed the Ga-incorporation in the CIGS crystal lattice. 15Abstract 16 In this paper, we report a novel and simple solution-based approach for the fabrication

7In this work, we investigated the properties of silver and gold enamels as potential back 8 contacts for Cu(In,Ga)Se2 (CIGS) solar cells. The enamels were deposited on ceramic 9 tiles by non-vacuum printing techniques. Thus, we are proposing a development of 10 integrated photovoltaic tile for the first time. We also explained the CIGS synthesis 11 procedure using co-precipitation of selenites precursors. To deposit the precursor 12 powders on the substrate, a doctor blade method is applied. The interface morphology 13 between ceramic tile, back contact, and CIGS absorber was studied as a critical factor 14 for the final solar cell performance. The thermal treatment effect on the back contact 15 properties was also reported. 16Excellent compatibility between CIGS and gold layer was observed, keeping thickness absorber were obtained when silver enamels were used.