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Towards Indium free TCOs

Periodic Reporting for period 1 - INREP (Towards Indium free TCOs)

Reporting period: 2015-02-01 to 2016-07-31

The goal of INREP is to develop and deploy valid and robust alternatives to Indium-based transparent conductive electrode materials. Indium-based materials are technologically entrenched in the commercial manufacture of components. However, the decreasing availability and increasing cost of Indium poses a threat to the European electronics industry which uses this material in abundance. In terms of volume, one of its main uses is in making transparent electrodes for components that interact with light. These include flat panel displays, flexible electronics, high efficiency photovoltaic cells and light emitting diodes (LEDs), both inorganic and organic, all devices in which Europe has societal and economic interests. As such, the possibility of shortages in the supply of Indium poses an evident challenge to the future development of the high added value electronic industry in Europe.
Replacing Indium-based materials with Indium-free transparent conducting oxides (TCOs) will require a holistic approach. To reach its overall goal, INREP brings in a multi-disciplinary consortium of industrial and academic partners with the required expertise to conduct research activities that will result in the creation of TCOs and their deposition technologies with the optimum opto-electrical properties for the economic and safe manufacture of opto-electronic components. The INREP partners will meet this challenge by addressing the value chain issues via an application-focused research aimed at developing solutions for the targeted applications.
Indium-free TCO thin films have been prepared by different deposition methods using ranges of deposition parameters for detailed analysis of their intrinsic properties in modeling and structural-property correlation. They will also provide the basis for optimum materials selection for the application activities.
The partners have also synthetized high performance alternatives to Indium-Tin oxide by means of gas phase and wet chemistry-based approaches for laboratory scale demonstration in the targeted applications: high efficiency photovoltaic cells, lighting (organic and inorganic LEDs) and touch-screens.
Needed advances in deposition technologies and tools were made for high layer uniformity in large area conditions, and for improved control on the damage induced by plasma processes.
Life Cycle Assessment analysis have been launched to assess the environmental impact of TCO deposition processes for different materials composition and deposition techniques. The analysis enables to quantify the impact on the environment over the entire period of the product life cycle (manufacturing, operation and waste management).
The INREP partners have also started evaluating the performance of the new TCO layers in a range of device technologies at a pre-production scale. These devices include: high efficiency solar cells, organic and inorganic LEDs and touch screens. This close collaboration with end users allows process steps to be developed that ensure the TCO can be incorporated into demonstrator devices which fully exploit the improved material properties. It will ensure that the layers developed closely match the requirements of real-world devices. Another aspect of the activities is the development of production capable deposition techniques with high throughput, high uniformity and low cost of ownership. This will ensure that the TCOs developed are compatible with industrial scale deposition processes and are suitable for commercial device production allowing the outcomes of the project to be exploited as soon as possible. The systems being developed cover a range of deposition technologies including Large Area (30mmx30mm) Spatial Atomic Layer Deposition (S-ALD) and plasma based systems. Development of the production scale systems has already begun and is already demonstrating high quality TCO layers.
The INREP partners have been working to produce a complete assessment of the relevant properties of the proposed TCOs, including the impact of deposition technique, to devise optimum processes for their application in selected, high value application areas. The selected application areas are organic and inorganic LEDs, solar cells and touch-screens. The physical properties of interest are transparency, electrical conductivity, work function, texture, and chemical and thermal stability. The approach includes life cycle assessments of the environmental impact of the developed TCO materials and cost of ownership analyses of their formation technologies over the entire period from application in manufacturing, through component operation into waste management. This analysis will enable a profound and objective assessment of sustainability of TCO materials. As a result, the environmental impact of TCO will be considered in the design of the final product, allowing to achieve the highest environmental quality of the TCO being developed to a manufacturing standard. Moreover, INREP brings innovative deposition equipment closer to an industrial level in order to accelerate the deployment of indium-free TCOs and achieve cost reduction for large area applications.
By relying on the new TCO material simulation and close integration of the developed solutions via its end-user partners, INREP have been creating a strong, competitive industrial base and a new knowledge in the field of sustainable transparent conductor material. The applications-led approach has been conceived to maximise the opportunities of economic deployment of the research outcomes of the project and reduce the time to their deployment. It is expected that by the end of the project the technical and commercial potential of the proposed Indium-free TCO solutions will be comprehensively demonstrated. Through the involvement of industrial end-users in the consortium, these solutions will also be “production-ready” for each of the targeted applications. The planned early take-up of the developed materials and processes will contribute to expand the partners’ market shares. For example, Plessey Semiconductor and Meyer Burger plan to incorporate Indium-free TCOs into respectively their growing LED production and high efficiency photovoltaic cells manufacturing lines. In this sense, the project has allowed to secure technology jobs and, in case of several partners, to increase their workforce.
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