Demonstration of Integrated roll-to-roll Assembly of Light Energy Harvester and Flexible Hybrid Electronics to Produce IoT Devices

The "ENLIGHTENED" project covers the entire value chain of organic PV for indoor applications in the manufacturing process of the OPV company Epishine, which specializes in this field. Fraunhofer ISE's role in the project, together with FAU Erlangen-Nürnberg and Epishine, involves the further development of OPV technology for indoor applications. Improved organic semiconductors are being developed for this purpose by partners Imperial College London and Brilliant Matters. The European Commission is funding the "ENLIGHTENED" project, which aims to redefine the standards for the production of cost-effective and environmentally friendly OPV applications for indoor use, thereby helping the products reach market maturity.

Initial Situation

More and more networked sensor systems require sustainable solutions for a permanent and maintenance-free energy supply indoors. The areas of application can range from digital price tags in supermarkets to tracking systems for tools in large companies. Even today, organic solar cells achieve higher efficiencies than the amorphous silicon currently in use under typical indoor lighting conditions. The integration of film-based organic photovoltaics (OPV) will become significantly easier in the future. In addition, these solar cells are unbreakable, which can be an advantage in harsher operating environments. The use of photovoltaics allows for a wider range of functions to be realized while avoiding battery replacement or significantly delaying it, which can reduce both costs and non-ecological waste products.

Objective

At Fraunhofer ISE, various new materials are being tested and cell structures investigated in order to increase the efficiency of cells and modules under artificial lighting to 30% and 25%, respectively, while ensuring sufficient durability under typical operating conditions.

Approach

To this end, Fraunhofer ISE is investigating materials for the contact layers and the organic semiconductor, which are being developed by its partners (Imperial College London, Brilliant Matters). It is testing these in various layer structures in order to systematically analyze the influences of the materials themselves, the coating sequence, and environmental conditions, thereby optimizing material selection and manufacturing processes. Requirements profiles and tests of the demonstrators in real application scenarios are defined by the partners in the end application (4MOD, Pricer). The partners Innovation Lab Heidelberg, Traxcon, and ONIO are developing effective and cost-efficient integration processes for the OPV and the electronic components in flexible components.

Interim Results

We have now achieved an efficiency of up to 25% under indoor lighting (warm white LED at 500 lux). The solar cells were very stable at elevated temperatures of 85°C. The project has thus already come a long way toward achieving its goals (efficiency of 30% for small solar cells and 25% for modules). However, the solar cells still degrade too quickly under illumination. New OPV materials synthesized by our partner Imperial College should enable further improvements, particularly in terms of long-term stability under illumination. To this end, a molecular structure identified as unstable is to be stabilized using various synthetic structural approaches.

• Epishine
• Pricer
• 4Mod Technology
• Imperial College of Science Technology and Medicine (ICL)
• Friedrich-Alexander-Universität Erlangen-Nürnberg
• Fraunhofer-GEsellschaft zur Förderung der angwandten Forschung EV
• ONIO AS (ONiO)
• Flexoo GmbH (Heidelberg)