Description
The photovoltaic (PV) module production costs still limit utilization of this energy source in common daily use. The n+/p and p/p+ junction formation in separate steps creates additional costs that can be lowered when in-line process is applied. The project is focused on developing simpler, environmentally benign and cheaper methods for silicon doping to form necessary junctions. The overall solar cell structure will be additionally improved by application of plasmonic particles, up- and/or down-converters of the light and thinning of the electrical paths. All the areas of activity will be covered by all project partners resulting in technological and scientific know-how exchange leading to partnership strengthening. The collaboration of the project partners will lead to new PV cell production technology. The PV module prototype produced with utilization of the project results will be one of the expected results. The efficiency of this module should be higher than the one produced in a traditional way but with lower costs. Therefore, all electricity consumers should be the beneficiaries of the project.
Summary of project results
The costs of photovoltaic (PV) module fabrication limit utilization of this energy source in common daily use. The n+/p and p/p+ junctions must be formed at semiconducting silicon surface by surface doping with phosphorus or boron. This doping process of silicon wafers is commercially implemented in separate steps that create additional costs. The costs can be lowered by when in-line process of junctions’ formation is applied. The InlinePV project was focused on developing simpler, environmentally benign and cheaper methods for silicon doping to form necessary junctions. This task was achieved for phosphorus or boron dopants applied on silicon wafers. The developed method utilized liquid sources of the dopants. The dopant solutions were composed of simple inorganic (phosphoric or boric acids) and organic compounds (alcohols). The applied compounds were neither toxic nor expensive contrary to the ones used in commercial processes. The sources were deposited at silicon surface by simple and cheap spray method allowing in-line application. The depth profiles of dopant distribution were adequate to the PV cell requirements. The phosphosilicate and borosilicate glasses formed at the silicon surface during high temperature doping process were much easier removable than the ones formed after commercial POCl3 or BBr3 dopants were used. The efficiencies of the cells fabricated with the use of developed sources were the same like obtained with application of POCl3 or BBr3 commercially used. Therefore, by application of developed doping system we were able to lower costs of environmental protection during the fabrication process, costs of chemical compounds used for doping process and costs of fabrication based on in-line technology. Additionally, the works on application of plasmonic particles and light converters at the front surface of the solar cells were performed. The results were scientifically interesting but light conversion effect was too low to be commercially applicable. As a proof of the developed technology five PV modules were fabricated.
Summary of bilateral results
The project allowed establishing and strengthening collaboration that resulted in achieving shared results and improved knowledge concerning methodology of silicon fabrication (SINTEF – Norwegian partner) and silicon doping by phosphorus and boron (IMMS and ICSC - Polish partners). The cooperation allowed access to the techniques and instrumentation available in partners’ laboratories and led to development of complementary techniques of synthesis of noble metal nanoparticles utilized in silicon texturization by application of metal assisted etching technique. It also allowed PhD students participating in the project to work in the international milieu and present the results of their work at international conferences. The funding of the project contributed to the strengthening of bilateral relations between partners that will results in common publications and applications for future projects. Organization and common participation in the InlinePV project workshop entitled “Materials and methods for cost-effective solar cell production” attracted industrial interest in developed solutions as well as in scientific and research capabilities of involved institutions that can lead to industrially focused projects in the future. The number of conference presentations (24 oral presentations and 12 posters) contributed to the project visibility among Polish and International researchers.