How the Starting Precursor Influences the Properties of Polycrystalline CuInGaSe2 Thin Films Prepared by Sputtering and Selenization

Abstract

Cu(In,Ga)Se 2 (CIGS)/CdS thin-film solar cells have reached, at laboratory scale, an efficiency higher than 22.3%, which is one of the highest efficiencies ever obtained for thin-film solar cells. The research focus has now shifted onto fabrication processes, which have to be easily scalable at an industrial level. For this reason, a process is highlighted here which uses only the sputtering technique for both the absorber preparation and the deposition of all the other materials that make up the cell. Particular emphasis is placed on the comparison between different precursors obtained with either In 2 Se 3 and Ga 2 Se 3 or InSe and GaSe as starting materials. In both cases, the precursor does not require any heat treatment, and it is immediately ready to be selenized. The selenization is performed in a pure-selenium atmosphere and only lasts a few minutes at a temperature of about 803 K. Energy conversion efficiencies in the range of 15%-16% are reproducibly obtained on soda-lime glass (SLG) substrates. Similar results are achieved if commercial ceramic tiles are used as a substrate instead of glass. This result is especially useful for the so-called building integrated photovoltaic. Cu(In,Ga)Se 2 -based solar cells grown directly on ceramic tiles are ideal for the fabrication of ventilated façades in low impact buildings.

The History of Photovoltaics with Emphasis on CdTe Solar Cells and Modules

“…The energy band gap profile was definitively stressed when, approaching the back contact, the Ga concentration was increased inside the CIGS layer. Consequently, a larger energy gap in the back-contact region was realized and a mirror for the minority carriers was obtained, increasing their diffusion length [49,50]. In this favorable condition, a 19.9% efficient solar cell was realized in 2008 [51].…”

Theoretical Design of the Absorber for Intermediate Band Solar Cells from Group‐IV (Si, Ge, and Sn)‐Doped AgAlSe2

“…At present, polycrystalline silicon solar cell remains the largest occupancy in the current commercial solar cells market . In addition, thin film solar cells based on Cu(In,Ga)Se 2 and Cu 2 ZnSn(S,Se) 4 have achieved the efficiency of 22.3 and 12.6% in the laboratory, respectively. Cu(In,Ga)Se 2 solar cell has also been put on the commercial market recently .…”

Diseño sostenible de materiales cerámicos multifuncionales para el suministro eléctrico de baja potencia.

“…Por ejemplo, en ciertos edificios públicos se utilizan celdas solares de silicio amorfo como un BIPV (Shah et al, 2004). Además, de las de silicio amorfo se han fabricado celdas del tipo CuInGaSe2 (Rosa, Bosio, Menossi, & Romeo, 2016) o Cu2ZnSn(S,Se)4 (Calvet et al, 2015) utilizando un sustrato cerámico tipo baldosa con miras a formar parte de un BIPV.…”

“…Los materiales cerámicos gracias a su resistencia química y ambiental; así como a sus excelentes propiedades mecánicas, térmicas y de dureza son utilizados en herramientas de corte, materiales de construcción, implantes dentales, etc., pero además su uso se ha extendido a áreas como la electrónica (Honma & Komatsuzawa, 1988), fotovoltaica (Reyes-Tolosa, Ajami, et al, 2010) y electroquímica (Currao, 2007). Específicamente, baldosas cerámicas han sido utilizadas como sustratos en la fabricación de celdas solares de CuInGaSe2 (Rosa et al, 2016), Cu2ZnSn(S,Se)4 (Calvet et al, 2015), orgánicas (Muller et al, 2014) y de silicio policristalino y amorfo (Carnel et al, 2006;Iencinella, 2009;Iencinella, Centurioni, & Grazia Busana, 2009;Mazzanti et al, 2008). Con este antecedente, se considera que un material cerámico puede ser utilizado como sustrato para el ensamblaje de dispositivos fotovoltaicos.…”