Electronic structure study of the CdS buffer layer in CIGS solar cells by X-ray absorption spectroscopy: Experiment and theory

Abstract

A systematic investigation of the electronic structure of the CdS buffer layer of CIGS solar cells has been undertaken using S Kedge X-ray absorption spectroscopy (XAS), both experimentally and theoretically. We found from XAS that growing CdS films by chemical bath deposition (CBD) exhibits more long-range disorder when compared to single crystal CdS, CdS grown by atomic layer deposition (ALD) and theory. We investigated the significance of a variety of point defects and potential atomic substitutions in firstprinciples estimates of the differential S Kedge XAS sensitivity. We find that substituting

Numerical Simulation for Enhancement of output Performance of WS2 based Thin Film Solar Cells

“…The WS2 absorption based modal is consist of four layers The window layer having thickness of 30nm is made of ZnO material, which is a promising candidate because it provides low series resistance, permits high optical transmission and electrical conduction, and cheaper in cost than other optical or Mg materials [22]. The buffer layer having thickness 45nm is made of ZnSe material, which has a wide bandgap of 2.42 eV and has good electrical properties, and is better in electrical transmission [23,24]. The active layer having thickness of 2500nm has also a wide bandgap and is responsible to trap highly energetic photons.…”

Band gap engineering of atomic layer deposited ZnxSn1‐xO buffer for efficient Cu(In,Ga)Se2 solar cell

“…However, there still remain many challenges that hinder the global commercialization of the CIGS technology, including the n ‐type cadmium sulfide (CdS) used as buffer layer. The narrow band gap of CdS results in parasitic absorption of high‐energy photons, which reduces the photo‐generated current of the cells . In addition, the toxicity of cadmium raises major health and environmental concerns forcing many countries to place bans on the importation and use of the technology .…”

“…In addition, the toxicity of cadmium raises major health and environmental concerns forcing many countries to place bans on the importation and use of the technology . Furthermore, CdS buffer layer is deposited by a nonvacuum chemical bath deposition process, and although the chemical bath deposition process offers a number of advantages including altering the CIGS interface to enhance device performance, it presents a major drawback in adopting a continuous vacuum‐based process for large‐scale cell/module fabrication . For these reasons, alternative cheap, environmentally friendly and equally efficient buffers are being explored to replace CdS.…”

“…The narrow band gap of CdS results in parasitic absorption of high-energy photons, which reduces the photo-generated current of the cells. 2,3 In addition, the toxicity of cadmium raises major health and environmental concerns forcing many countries to place bans on the importation and use of the technology. 4 Furthermore, CdS buffer layer is deposited by a nonvacuum chemical bath deposition process, and although the chemical bath deposition process offers a number of advantages including altering the CIGS interface to enhance device performance, 2 it presents a major drawback in adopting a continuous vacuum-based process for large-scale cell/module fabrication.…”

Annealing time effect on the optical properties of Zn(O,OH,S) films onto ZnO seed layer under un-vacuum ambient

“…(CIGS)-solar cells have a layer that called as 'buffer layer' which has a relatively critical precaution for reducing the interface recombinations, decreasing the mechanical tension stress between absorbent layer/TCO electrode and providing optimal band alignment throughout the junction. CdS film preferred as a buffer layer between i:ZnO window and CIGS absorbent is produced by frequently atomic layer deposition (ALD) or chemical bath deposition (CBD) [4,5]. In the buffer layer studies, cadmium-free alternative material necessity occurs due to CdS has high toxicity, the narrow band gap energy (~2.4 eV) and high interface recombinations between the absorber and window interface [6].…”