Advances in CuInSe2 and CdTe thin film solar cells (original) (raw)

Impact of the Cd2+ treatment on the electrical properties of Cu2ZnSnSe4 and Cu(In,Ga)Se2 solar cells

Progress in Photovoltaics: Research and Applications, 2015

The present contribution aims at determining the impact of modifying the properties of the absorber/buffer layer interface on the electrical performance of Cu2ZnSnSe4 (CZTSe) thin‐film solar cells, by using a Cd2+ partial electrolyte (Cd PE) treatment of the absorber before the buffer layer deposition. In this work, CZTSe/CdS solar cells with and without Cd PE treatment were compared with their respective Cu(In,Ga)Se2 (CIGSe)/CdS references. The Cd PE treatment was performed in a chemical bath for 7 min at 70 °C using a basic solution of cadmium acetate. X‐ray photoemission spectroscopy measurements have revealed the presence of Cd at the absorber surface after the treatment. The solar cells were characterized using current density–voltage (J–V), external quantum efficiency, and drive‐level capacitance profiling measurements. For the CZTSe‐based devices, the fill factor increased from 57.7% to 64.0% when using the Cd PE treatment, leading to the improvement of the efficiency (η) fro...

Low-cost deposition of CuInSe 2 (CIS) films for CdS/CIS solar cells

Solar Energy Materials and Solar Cells, 1998

We discuss in this paper the development of inexpensive, high efficiency, large-area solar cells of the type thin-film ZnO/CdS/Cu(In,Ga)Se . It has been shown recently in research laboratory tests that polycrystalline thin-film cells of this general composition deposited onto inexpensive soda-lime glass substrates have solar-to-electric conversion efficiencies exceeding 17%. These small-area cells were deposited using vacuum technology which is difficult and expensive to scale up in area to square-meter flat-plate modules in a manufacturing arena. We discuss in this paper inexpensive, non-vacuum deposition technology which is inherently scalable to largearea deposition. We pay particular attention to electrodeposition of multilayer binary or ternary selenide precursors to be thermally annealed to form Cu(In,Ga)Se films of appropriate overall composition, elemental grading and smoothness.

Fabrication of Cd-free CuInSe2 solar cells using wet processes

Journal of Materials Science, 2017

CuInSe 2 has become an attractive material for use in the production of thin-film solar cells. Recently, energy conversion efficiencies over 20% have been achieved by CuInSe 2 solar cells created using vacuum processes. To reduce manufacturing costs, more recent efforts have focused on non-vacuum processes. In this study, we fabricated solar cells exclusively by wet processes. CuInSe 2 absorption layers and In 2 S 3 buffer layers were electrochemically or chemically deposited, and ZnO window layers were formed using solutionbased chemical methods. The deposited CuInSe 2 absorption layers were heattreated to improve crystallinity. We deposited a Cd-free buffer layer of In 2 S 3 using a chemical bath method on the CuInSe 2 absorption layers, and then ZnO window layers were deposited by a solution-based process. With this system, we successfully fabricated CuInSe 2 solar cells and obtained a cell efficiency of 2.38%.

Development of thin-film Cu(In,Ga)Se2 and CdTe solar cells

Progress in Photovoltaics: Research and Applications, 2004

Cu(In,Ga)Se 2 and CdTe heterojunction solar cells grown on rigid (glass) or flexible foil substrates require p-type absorber layers of optimum optoelectronic properties and n-type wide-bandgap partner layers to form the p-n junction. Transparent conducting oxide and specific metal layers are used for front and back electrical contacts. Efficiencies of solar cells depend on various deposition methods as they control the optoelectronic properties of the layers and interfaces. Certain treatments, such as addition of Na in Cu(In,Ga)Se 2 and CdCl 2 treatment of CdTe have a direct influence on the electronic properties of the absorber layers and efficiency of solar cells. Processes for the development of superstrate and substrate solar cells are reviewed.

Highly efficient CuInS2 based solar cell devices with an optimized Cd free window structure

ZnS thin films deposited in a chemical bath have been studied for use as buffer layers in CuInS 2 ("CIS") based solar cell devices. The ZnS films were grown on CIS using aqueous solutions containing zinc sulphate (ZnSO 4 · 7 H 2 O) mixed with thiourea (SC(NH 2 ) 2 and ammonia (NH 3 ) at 70-80°C. In order to investigate the growth kinetics as well as the composition of the deposited nominal ZnS layers on CIS absorbers the deposition time was varied. A respective sample series was characterized by x-ray photoelectron spectroscopy (XPS) and x-ray excited Auger electron spectroscopy (XAES). It was found that the Zn-compound buffer layer is actually a bi-layer of an ultra-thin ZnS film followed by a mixture of ZnS and ZnO. The ZnS/(ZnS+ZnO) ratio of the latter Zn(S,O) layer was determined to be around 80 %. Corresponding solar cell devices with a [Zn(S,O)/ZnS] bi-layer buffer reach only then comparable efficiencies than references with CdS buffer layers when they undergo a light-soaking treatment prior to the characterization of their photovoltaic performance. However, if one further modifies the ZnO:Al/i-ZnO/CdS standard window (and thus optimizes it towards a competitive Cd-free window) by replacing not only the CdS by a [Zn(S,O)/ZnS] buffer but also by application of a (Zn,Mg)O instead of a i-ZnO layer, respective Cd-free solar cells reach the efficiencies of references with standard window without any (or reduced) lightsoaking. This is demonstrated for devices on the laboratory-scale and for mini-modules. Temperature dependent currentvoltage measurements are used to determine the dominant recombination mechanism of CIS based solar cells with this alternative ZnO:Al/(Zn,Mg)O/[Zn(S,O)/ZnS] window structure.

The preparation and properties of CuInSe(2) thin films and CuInSe(2)/CdS thin film solar cells

1997

CuInSesb2 and the related I-III-VIsb2 ternary chalcopyrite compounds and alloys are semiconductors suitable for use as absorbers in thin film solar cells. A three source coevaporation system for the growth of CuInSesb2 films, a hot wall evaporation system for CdS films, and a radio frequency sputtering system for Mo films are described. Demonstration Mo/CuInSesb2/CdS solar cells are produced to verify that the Mo, CuInSesb2 and CdS films are of acceptable photovoltaic quality. CuInSesb2 film samples are deposited on Corning 7059 glass for a detailed study of their properties. The Se is evaporated at a rate about three times the rate required for stoichiometry, so that the films are fully selenized. The Cu and In sources are positioned so that the Cu/In ratio varies by about 10% across the film area. This allows many of the properties to be measured as a function of the Cu/In ratio, on one substrate. Most other parameters which can effect film properties, such as film thickness, subs...

The role of the CdS buffer layer in the CuInS2 Thin film solar cell

Revue des Energies …

In this contribution, we report some studies on cadmium sulphide CdS thin films grown by Chemical Bath Deposition (CBD) process. The effect of the single and multiple dips deposition processes by using novel chemical bath on the thickness of the CdS obtained are investigated. The obtained results were used to study the influence of the layer thickness of the CdS on the performance of CuInS2 based solar cells. Several hetero-junctions of ZnO/CdS/CuInS2 type with different thickness of the CdS layer have been prepared and the devices properties are measured under AM1.5 solar spectrum. Résumé-Dans cette contribution, nous rapportons des études sur le sulfure du cadmium CdS en couches minces élaboré par le processus de dépôt par bain chimique (CBD). L'effet de la simple et multiple déposition utilisant des bains chimiques nouveaux sur l'épaisseur des couches de CdS a été étudié. Les résultats obtenus ont été utilisés pour étudier l'influence de l'épaisseur de la couche des CdS sur la performance des cellules solaires à base de CuInS2. Plusieurs hétérojonctions de type ZnO/CdS/CuInS2 avec différentes épaisseurs de la couche de CdS ont été préparées et leurs propriétés photovoltaïques ont été mesurées sous spectre solaire AM1.5.

CuInSe2 based solar cell structures by CVTG

Applied Energy, 1995

Chemical vapor transport by gas (CVTG) is a new method to grow semiconductor thin fihns, transparent conductors and hence solar cell structures economically. This technique can be divided into (1) reactive CVTG (R C VTG), and (2) condensation C VTG (C C VTG). In the present study CulnSe: film is formed by RCVTG and a CdS film is deposited by CCVTG to form solar cell structures like Mo/CIS/CdS/SnO2. Electroless deposited Cu-ln alloy, the precursor, was subjected to selenization at 500°C by an RCVTG method to produce the CIS film. The CdS film is deposited by CCVTG. Initial results show promising cell parameters for CVTG deposited CIS based solar cell structures. Detailed studies are in progress to characterize the influence of CVTG deposited CIS and CdS film properties on cell efficiency .and other cell parameters.

A novel cadmium free buffer layer for Cu(In,Ga)Se2 based solar cells

Solar Energy Materials and Solar Cells, 1996

Solar cellsbased on Cu(In,Ga)Se 2 were prepared replacing the "standard buffer layer" CdS with a Inx(OH,S)y thin film. The film is deposited in a chemical bath (CBD) process using an aqueous solution containing InCl 3 and thioacetamide. X-ray photoemission spectroscopy measurements were performed in order to characterize the growth kinetics and the chemical composition. The influence of different concentrations of InC13 and thioacetamide in the solution on the electrical properties of the solar cells was studied by measuring the j-V characteristics and the spectral quantum efficiencies. Capacitance-voltage (C-V) measurements indicate that the high V~, values of devices with the novel buffer layer are correlated with narrower space charge widths and higher effective carrier concentrations in the absorber materials. The achieved conversion efficiency of 15.7% (active area) using the cadmium free Inx(OH,S)y buffer demonstrates the potential of this process as an alternative to the standard chemical bath deposition of CdS.

Cu(In,Ga)Se2 thin film solar cells with buffer layer alternative to CdS

Solar Energy, 2004

Progress in fabricating Cu(In,Ga)Se 2 (CIGS) solar cells with ZnS(O,OH) buffer layers prepared by chemical bath deposition (CBD) is discussed in this paper. Such buffer layers could potentially replace CdS in the CIGS solar cell. Total-area conversion efficiency of up to 18.6% has been reported previously using ZnS(O,OH) prepared by CBD. The reported 100 nm CBD ZnS(O,OH) layer was prepared by at least three consecutive depositions, which would make it a relatively expensive replacement for CdS. The recent development of a ZnS(O,OH) layer that enabled to obtain highefficiency devices using a single-layer CBD is reported in this paper. A 14.4%-efficient device is obtained by using onelayer CBD ZnS(O,OH) on commercial-grade Shell Solar Cu(In,Ga)(S,Se) 2 (CIGSS) absorber and an up to 17.4% device is obtained by using two-layer CBD ZnS(O,OH) on an NREL CIGS absorber. 9:34 a.m.