Formation and Characterization of Electroless-Deposited NiTe[sub 2] Back Contacts to CdTe /CdS Thin-Film Solar Cells

Abstract

The preparation and characterization of NiTe 2 back contacts to CdTe/CdS cells are described. NiTe 2 is formed on p-CdTe by electroless deposition at low reductant concentrations, producing devices that are superior ͑conversion efficiencies often exceeding 10%͒ to those contacted with electroless Ni. X-ray photoelectron spectroscopy and X-ray diffraction showed the product to be nickel͑II͒ ditelluride (Ni 2ϩ Te 2 2Ϫ), produced, in the catalytic presence of Al 3ϩ ions, by the reaction of Ni 2ϩ ions with a Te-rich CdTe surface, which is formed by an in situ etch in the chemical bath. Preliminary results indicate that Ni, from NiTe 2 , is not mobile within the cell structure, which is expected to be favorable for stability. Cells exhibit degradation when exposed to H 2 O vapor. However, this effect was found to be reversible, with performance improving to near predegradation values following cell transfer to dry air conditions.

Unconventionally Layered CoTe2 and NiTe2 as Electrocatalysts for Hydrogen Evolution

“…[5,15] Literature values of the Ni 2p 3/2 binding energy of elemental Ni portray av arianceo f0 .3-0.5 eV from that of NiTe 2 . [5,15] Literature values of the Ni 2p 3/2 binding energy of elemental Ni portray av arianceo f0 .3-0.5 eV from that of NiTe 2 .…”

“…861.0 eV (Figure 3c)n oted for NiTe 2 has also been sighted in XPS studies performed on other nickel chalcogenidesw hereby Ni undertakesa no xidation state of + 2. [5,15] XPS deconvolution of Te 3d spectra for CoTe 2 and NiTe 2 (Figure 3b and c) shows strong resemblance to each other.B oth reveal ap air of doublets that is characteristic of MTe 2 (M = Co, Ni)a nd Te O 2 species. [19] As inferred, NiTe 2 is ap aramagnet.…”

“…This deduction achievesa consensus with earlier works documenting the weakp aramagnetic nature of NiTe 2 . [13,15,21] Given that the oxidation state of the transition metal Co and Ni is + 2, the Te speciesi nC oTe 2 and NiTe 2 is formulated to be Te 2 2À .B ensch et al had also arriveda tasimilarc onclusion. [5,15] XPS deconvolution of Te 3d spectra for CoTe 2 and NiTe 2 (Figure 3b and c) shows strong resemblance to each other.B oth reveal ap air of doublets that is characteristic of MTe 2 (M = Co, Ni)a nd Te O 2 species.…”

Fabrication of CdTe/NiTe films on Ni foils by radio-frequency magnetron sputtering method

“…Compounds, rather than metal element, do not allow diffusion of their basic components [39,40]. Recently, much effort has been devoted to preparing various compounds, including Ni phosphides and tellurides (Sb 2 Te 3 , NiTe 2 ) [39,41,42] with a nickel-arsenide-type structure, which can be employed as Ohmic contacting layer of CdTe solar cells for their distinctive electrical transport property [43]. Traditionally, NiTe can be synthesized by hydrothermal method or high temperature solid-state reaction [44,45], which require high energy consumption and relatively long reaction times.…”

Nickel Dichalcogenide Hollow Spheres: Controllable Fabrication, Structural Modification, and Magnetic Properties

“…[4] Furthermore, NiTe 2 is a promising back contact to CdTe/CdS solar cells with exceeding 10 % conversion efficiencies. [5] A variety of chemical and physicochemical methods, such as solid-state synthesis, elemental direct reaction, and mechanical alloying have been used to fabricate nickel dichalcogenides; nevertheless, there is barely a report about the synthesis of NiS 2 , NiSe 2 , and NiTe 2 hollow spheres up to now, partly due to the difficulties in fabricating transition-metal dichalcogenides with regular morphologies. [6] Herein, we have successfully devised a simple and general hydrothermal synthetic route to prepare the uniform NiS 2 hollow spheres in the presence of l-cysteine and urea.…”