High-efficiency Multi-junction Solar Cells Research Articles

Advances in amorphous silicon alloy technology—the achievement of high-efficiency multijunction solar cells and modules

Thin-film amorphous silicon alloy technology has emerged as a strong contender for providing low-cost photovoltaic products to meet the energy needs of the 21st century. World record 14·6% initial and 13·0% stable active-area conversion efficiencies have been achieved for small-area solar cells in our laboratory using a spectral-splitting, triple-junction structure. This 0·25-cm2 device exhibited a total-area efficiency of 12·0%, as confirmed by the National Renewable Energy Laboratory. Key factors leading to this achievement will be discussed. We have also demonstrated a 10·2% stable module efficiency for a one-square-foot area. A state-of-the-art, continuous roll-to-roll production line with an annual capacity of 5 MW has been built and started production. Building-integrated photovoltaic applications are being demonstrated worldwide. Public awareness of environmental and ecological issues has provided a great opportunity for the maturing thin-film amorphous silicon alloy technology to demonstrate its viability as a major alternate energy source. © 1998 John Wiley & Sons, Ltd.

Photoluminescence analysis of InGaP top cells for high-efficiency multi-junction solar cells

A way of evaluate the minority-carrier lifetime by using photoluminescence (PL) measurement is proposed which includes self-absorption. The room-temperature PL intensity is analyzed theoretically for bulk crystals and a device with n +-p junction configuration, based on a one-dimensional model. Photoluminescence analysis of In 0.5Ga 0.5P solar cells grown on GaAs and Si substrates by MOCVD (metal organic vapor deposition) have been carried out and compared with the properties of the In 0.5Ga 0.5P solar cells. By improving minority-carrier lifetime, high-efficiency In 0.5Ga 0.5P cells on GaAs substrates with an efficiency of 18.5% have been made.

Present status and future prospects of super high efficiency III–V compound solar cells

This paper presents recent development, cost analysis and possible applications of super high-efficiency III–V compound semiconductor solar cells. Japanese R&D programs of these solar cells in the New-Sunshine project of MITI (Ministry of International Trade and Industry) is briefly described. It also discusses future predictions for the super high-efficiency multi-junction solar cells.

Chemical beam epitaxy as a breakthrough technology for photovoltaic solar energy applications

Chemical beam epitaxy (CBE) is a possible breakthrough technology for photovoltaic (PV) solar energy applications. This paper reviews the present status of epitaxial technologies for high-efficiency III-V compound semiconductor solar cells. It also discusses the advantages of CBE technology over metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) for III-V compound solar cell fabrication. CBE and related growth technologies can effectively produce high-efficiency and low-cost multi-junction III-V compound solar cells. Moreover, CBE may possibly reduce solar cell fabrication costs in the future because it utilizes source materials more efficiently than MBE and MOCVD. The cost of solar cell fabrication using CBE are estimated and compared with those using MOCVD and MBE.

Review of high efficiency multijunction and point contact GaAs solar cell development

Review of high efficiency multijunction and point contact GaAs solar cell development

Physics of High Efficiency Multijunction Solar Cells

AbstractWe have shown that high efficiency solar cells can be obtained by incorporating materials of different band gaps in a multijunction configuration. This configuration gives rise to high efficiency due to spectrum splitting as well as superior stability due to thin top cells.We have fabricated multijunction solar cells and acheived a 13% conversion efficiency using 1.7eV a-Si:F:H and 1.5 eV a-Si:Ge:F:H materials in a three-cell triple configuration. This device was deposited onto a stainless steel substrate coated with a back reflector; it also incorporates a microcrystalline p+ layer.The physical properties of each of the solar cell layers and their role in the device physics of a high efficiency solar cell will be described.

Critical Materials Parameters for the Development of Amorphous Silicon Alloys

AbstractThe desired properties of solar cells are discussed, and a relative figure of merit for the comparison of cells fabricated using different technologies is described. The advantages of utilizing amorphous silicon alloys as the active material in solar cells are enumerated. Selected materials properties of these alloys are described and the physics of their electronic structure is discussed in detail. The necessary steps for achieving commercially viable cells based on amorphous silicon alloys are listed, and it is demonstrated how each of them has been achieved using a technology that incorporates fluorine throughout the entire process. The chemical and physical basis for the superiority of fluorinated material is presented in detail. Continuous web large-area high-efficiency multijunction solar cells are in production. Dual band gap multijunction cells have been tested under continuous air mass 1 exposure for over 2000 hours and show essentially no degradation. Some recent results are presented.

IVA-1 high efficiency multi-junction solar cells

IVA-1 high efficiency multi-junction solar cells