CGS based solar cells with In2S3 buffer layer deposited by CBD and coevaporation

Abstract

In this paper we investigated In 2 S 3 as substitute for CdS, which is conventionally used as buffer layer in chalcopyrite based solar cells. In 2 S 3 thin films were deposited by CBD and co-evaporation methods and these were employed as buffer layer in CuGaSe 2 based solar cells. Previous to the device fabrication, comparative study was carried out on In 2 S 3 thin films properties deposited from chemical bath containing thioacetamide, Indium Chloride, and sodium citrate, and In 2 S 3 thin films prepared by co-evaporation from its constituents elements. The influence of synthesis conditions on the growth rate, optical, structural and morphological properties of the as-grown In 2 S 3 thin films have been carried out with Spectrophotometry, X-ray diffraction and AFM microscopy techniques. Suitable conditions were found for reproducible and good quality In 2 S 3 thin films synthesis. By depositing In 2 S 3 thin films as buffer layers in CuGaSe 2 configuration, a maximum solar cell efficiency of 6% was achieved, whilst the reference solar cell with CdS/CuGaSe 2 on similar absorber exhibited 7% efficiency.

Caracterización fisicoquímica del sistema Mo/CuInS2/Zn(O,OH)S/ZnO por medio de espectroscopía fotoelectrónica XPS y AES

“…El Zn(O,OH)S es uno de los principales candidatos para obtener capas buffer libres de Cd con eficiencias comparables; esta capa tiene una E g de 3.8 eV y no presenta ningún riesgo ambiental. El método Chemical Bath Deposition (CBD) ó deposición de baño químico (en español) ha sido ampliamente utilizado para la síntesis de las películas buffer debido a su bajo costo de implementación, las temperaturas de síntesis son bajas, y este método permite recubrir con facilidad grandes superficies sin deteriorar la capa absorbente [6], actualmente las celdas solares que utlizan capas buffer de Zn(O,OH)S sintetizadas por CBD han presentado eficiencias 18.8 % [7] muy cercanas a las máximas reportadas cuando se utiliza el CdS, la incorporación de este tipo de capas buffer en remplazo de las capas de CdS sin disminuir significativamente la eficiencia del sistema fotovoltaico representa un avance significativo en el área. En este trabajo se sintetizaron capas de Zn(O,OH)S sobre capas absorbentes de CuInS 2 , como remplazo de la tóxica y ambientalmente peligrosa capa buffer de CdS.…”

Kinetic study on Zn(O,OH)S thin films deposited by chemical bath deposition

“…Those cells includes a very thin chemical-bath-deposited (CBD) CdS buffer layer in their structure; however different environmental problems associate to CdS and the possibility of increasing the value of the current of short circuit (Jsc), have generated great interest in the development of Cd-free buffer layers [2]. Different materials as In 2 S 3 , In 2 Se 3 , ZnSe deposited by different methods have demonstrated good results as alternatives buffer layers in chalcopyrite based solar cells [3,4]. On the other hand, CIGS based cells Zn(O,OH)S-based buffer layers prepared by CBD have already demonstrated their potential as alternative buffer material; efficiencies up to 18.6% have been obtained using ZnS(O,OH)/ZnO as window layer in CIGS based solar cells [5].…”

Progress in indium (III) sulfide (In 2 S 3 ) buffer layer deposition techniques for CIS, CIGS, and CdTe-based thin film solar cells

“…In the past, various metal sulfides, oxides, and oxy-sulfides such as CdS, In 2 S 3 , In x Se y , ZnS, ZnSe, ZnO, SnO 2 , Zn 1Àx Mg x O, and In x (OH,S) y . have been investigated and used in manufacturing TFSCs (Dimova-Malinovska, 2010;Ahn et al, 2008;Vallejo et al, 2010).…”

“…The absorber layer, in which photons are efficiently absorbed resulting in electron-hole pair generation, constitutes the core of the device (Wü rfel, 2005). However, in this paper, we focus upon the buffer layer (In 2 S 3 ) whose principal goal is to form a reliable p-n junction and establish good interface properties with the absorber layer, while allowing maximum transmission of light (minimum absorption loss) to both the junction region and the absorber layer (Vallejo et al, 2010). In addition, it passivates the junction region, allowing absorber materials better suited for environmental exposure, hence providing stability to the solar cell (Roedern, 2001).…”