Welmoed Veurman

Status of Dye Solar Cell Technology as a Guideline for Further Research

Recently, the first commercial dye solar cell (DSC) products based on the mesoscopic principle were successfully launched. Introduction to the market has been accompanied by a strong increase in patent applications in the field during the last four years, which is a good indication of further commercialization activity. Materials and cell concepts have been developed to such extent that easy uptake by industrial manufacturers is possible. The critical phase for broad market acceptance has therefore been reached, which implies focusing on standardization-related research topics. In parallel the number of scientific publications on DSC is growing further (>3500 since 2012), and the range of new or renewed fundamental topics is broadening. A recent example is the introduction of the perovskite mesoscopic cell, for which an efficiency of 14.1% has been certified. Thus, a growing divergence between market introduction and research could be the consequence. Herein, an attempt is made to show that such an unwanted divergence can be prevented, for example, by developing suitable reference-type cell and module concepts as well as manufacturing routes. An in situ cell manufacturing concept that can be applied to mesoscopic-based solar cells in a broader sense is proposed. As a guideline for future module concepts, recent results for large-area, glass-frit-sealed DSC modules from efficiency studies (6.6% active-area efficiency) and outdoor analysis are discussed. Electroluminescence measurements are introduced as a quality tool. Another important point that is addressed is sustainability, which affects both market introduction and the direction of fundamental research.

Glass Frit Dissolution Influenced by Material Composition and the Water Content in Iodide/Triiodide Electrolyte of Dye-Sensitized Solar Cells

To ensure long-term stable dye-sensitized solar cells (DSCs) and modules, a hermetic sealing is required. This research investigates the chemical stability of redox electrolyte and four different glass frits (GFs). Sintered GF layers were openly exposed to nonaqueous redox electrolyte and redox electrolyte with 1, 5, and 10 wt% H2O in thin, encapsulated cells. The change in absorbance was assigned to a reaction between the GF and electrolyte and was used to evaluate the chemical stability of the different GFs. The absorbance change was monitored over 100 days. Two out of the four GFs were unstable when H2O was added to the redox electrolyte. The H2O caused metal ion leaching which was determined from EDX analysis of the inorganic remains of electrolyte samples. A GF based on Bi2O3–SiO2–B2O3 with low bond strength leached bismuth into electrolyte and formed the complex. A ZnO–SiO2–Al2O3-based GF also became unstable when H2O was added to the redox electrolyte. Leaching of zinc ions due to exchange with H

Scaling-up of glass based DSC-modules for applications in building integrated photovoltaics

Within the German research projects ColorSol and InnoCo, a focus is put on the scaling-up of glass based dye solar cell modules and the development of a production technology. This paper reports on the successful scaling-up from 30 * 30 cm to 60 * 100 cm prototypes. First characteristics of these modules are lined out. The developed modules aim for applications in building integrated photovoltaic e.g. façades and PV-glazing. Size and technical specification of the modules follow requirements that were evaluated with architects and partners from the façade industry. For a future production partners for the value chain are being actively searched and integrated to create a network and a value chain on building integrated photovoltaics (BIPV) and façade applications.

Introduction to in-Situ Produced Perovskite Solar Cells; a New Concept towards Lowest Module Manufacturing Costs

Starting from the glass frit procedure developed to seal dye solar cells, research is being conducted at Fraunhofer ISE on optimizing and upscaling the principle of perovskite solar cells by an in-situ coating method. A process is proposed, in which the porous substrate films can be filled in sequence with the dissolved active materials of the perovskite solar cell. By varying the porosity and the particle size in the substrate films, the active materials can be deposited in a self-organised process by capillary forces, and form the solar cell after drying. Specially designed structures in the glass substrate make the transport and inert drying of the solvent feasible. The procedure will enable future perovskite solar modules to be produced with minimal consumption of resources and at very low costs. In this paper, we report and comment on our results from proof of principle and about the on-going work in this new area.

Monolithic Perovskite Silicon Tandem Solar Cells with Advanced Optics

To realize high efficiency monolithic perovskite silicon tandem solar cells, we develop low-temperature processes for the perovskite top cell, rear-side light trapping, optimized perovskite growth, transparent contacts and recombination interconnection layers, and adapted characterization methods.