We report on the analytical description of high-efficiency Cu(In,Ga)Se2-based solar cells produced with a static coevaporation process. We discuss classic quality markers such as grain morphology, ...composition, vertical compositional gradings, and grain orientation in these cells. We then describe the successful transfer of such results to industrially relevant inline processes in our module production line. Finally, we explicate one of the many optimisation routes for the further improvement of these Cu(In,Ga)Se2-based solar cells: Zn(O,S) buffer layers.
•Quality markers of high-efficiency Cu(In,Ga)Se2 (CIGS) cells re-examined.•Efficiency development of CIGS modules.•Zn(O,S) alternative buffer optimization.•Technology transfer from lab to industry
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Perovskite‐based multijunction solar cells can potentially overcome the power conversion efficiency (PCE) limits of established solar cell technologies. The technology combines high‐efficiency ...perovskite top solar cells with crystalline silicon (c‐Si) and copper indium gallium diselenide (CIGS) single‐junction solar cells enabling a more efficient harnessing of solar energy. In this work, we present high‐efficiency and scalable perovskite‐CIGS and perovskite‐Si multijunction solar modules in a four‐terminal configuration. We design the multijunction solar modules for minimal optical losses through careful optical engineering. In addition to optimized light coupling, the solar modules are fabricated in a scalable device design. Starting from lab‐scale cells of 0.13 cm2, we scale up the multijunction devices by two orders of magnitude to 16 cm2 and investigate the various losses affecting the PCE of large‐area multijunction solar modules, thus providing valuable insights into scalability of the technology. The champion perovskite‐CIGS and perovskite‐Si multijunction solar modules exhibit higher PCE than the stand‐alone devices on sizes up 16 cm2, paving the way for high‐effiency perovskite‐based multijunction photovoltaics. This work brings to forth relevant upscaling aspects of perovskite‐based multijunction solar cell technology, which is a key milestone in the road to commercial feasibility of the perovskite‐based multijunction solar cell technology.
This work demonstrates the path to efficient transition of perovskite‐silicon and perovskite‐CIGS multijunction photovoltaic devices from small‐area cells toward large‐area modules.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this article, we discuss the leading thin-film photovoltaic (PV) technology based on the Cu(In,Ga)Se2 (CIGS) compound semiconductor. This contribution includes a general comparison with the ...conventional Si-wafer-based PV technology and discusses the basics of the CIGS technology as well as advances in world-record-level conversion efficiency, production, applications, stability, and future developments with respect to a flexible product. Once in large-scale mass production, the CIGS technology has the highest potential of all PV technologies for cost-efficient clean energy generation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, Deep Level Transient Spectroscopy (DLTS) measurements have been performed on Cu(In,Ga)Se
2
(CIGS) solar cells from an inline co-evaporation system. The focus of this investigation is ...directed on the effect of rubidium-fluoride (RbF)-post-deposition treatment (PDT) on the defects in the CIGS absorber layer. Different traps can be identified and their properties are calculated. Herein, different methods of evaluations have been used to verify the results. Specifically, one minority trap around 400 meV was found to show a significant reduction of the trap density due to the alkali treatment. In contrast, a majority trap at approximately 600 meV is unaffected.
We present a method for high-rate solution growth of the Zn(O,S) buffer layer to achieve deposition rates and material consumptions far below the standard Zn(O,S) and CdS deposition method. We ...replace the organosulfide thiourea by the more quickly decomposable thioacetamide and control the reaction kinetics by the use of chelating ligands and ammonia. We characterize the produced layers by secondary neutral mass spectrometry, X-ray diffraction, and optical transmission. For cell preparation, we use high-efficiency Cu(In,Ga)Se 2 with an alkali-modified surface, as well as industrially relevant inline absorber material. We realize a certified 21% cell efficiency with the standard thiourea-based Zn(O,S) and first cells with over 19 % with the high-rate Zn(O,S) buffer.
Alkali-fluoride post-deposition treatments (PDTs) of Cu(In,Ga)Se2 (CIGS) absorbers have repeatedly resulted in device efficiency improvements, observed mainly due to an open-circuit voltage (Voc) ...enhancement. Replacement of the CdS buffer layer with a higher band gap alternative can increase the short-circuit current density (Jsc) and also eliminate the use of Cd. In many alternative-buffer attempts, however, the Jsc gain was accompanied by a Voc loss, resulting in some degree of performance loss. In order to better understand the impact of RbF-PDT, we analyze a combination of experimental devices produced in the same in-line CIGS run with and without RbF-PDT in combination with chemical-bath-deposited CdS and Zn(O,S) buffers. Low-temperature current–voltage curves indicate a difference in Rb impact on the CIGS/CdS and CIGS/Zn(O,S) p-n junctions. For example, the diode-current barrier which creates a rollover often observed in RbF-treated CIGS/CdS current–voltage curves is significantly reduced for the CIGS/Zn(O,S) junction. Although the RbF-PDT had a positive impact on both junction partner combinations, the CIGS/Zn(O,S) devices' Voc and fill factor (FF) benefited stronger from the RbF treatment. As a result, in our samples, the Jsc and FF gain balanced the Voc loss, thus reducing the efficiency difference between cells with CdS and Zn(O,S) buffers.
Big sets of experimental data are key to assess statistical device performance and to distill underlying trends. This insight, in turn, can then be used to improve on the fabrication process. We here ...describe a standardized and optimized inline fabrication process and present a statistical analysis of tens of thousands of cells with chalcopyrite‐type Cu(In,Ga)Se2 absorber. The large number of samples allows us to point out where Ag alloying into the absorber offers improvements, and how it couples with compositional and optoelectronic properties. Solar cell parameters as a function of chemical composition of the absorber highlight the importance of fill factor on overall cell performance. Finally, we calculate losses in open‐circuit voltage as a function of band gap energy and show that radiative losses can be reduced by increasing the amount of Cu and/or Ag.
A standardized and optimized inline manufacturing process is established allowing for the rapid and reproducible fabrication of CIGS solar cells. A large‐scale statistical analysis of over 48,000 similarly prepared cells with varying absorber compositions reveals the combined impact of Cu‐ and Ga‐content on cell performance. The effect of Ag‐alloying into the absorber is discussed as well as the dependence of VOC losses on chemical composition.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
Big sets of experimental data are key to assess statistical device performance and to distill underlying trends. This insight, in turn, can then be used to improve on the fabrication ...process. We here describe a standardized and optimized inline fabrication process and present a statistical analysis of tens of thousands of cells with chalcopyrite‐type Cu(In,Ga)Se
2
absorber. The large number of samples allows us to point out where Ag alloying into the absorber offers improvements, and how it couples with compositional and optoelectronic properties. Solar cell parameters as a function of chemical composition of the absorber highlight the importance of fill factor on overall cell performance. Finally, we calculate losses in open‐circuit voltage as a function of band gap energy and show that radiative losses can be reduced by increasing the amount of Cu and/or Ag.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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