More info about tandem technology?
Watch the webinar 'Innovations in solar energy technologies'
Why tandem pv is Relevant
The high efficiency offered by tandem PV contributes to reducing overall PV electricity generation costs, and is important to reduce the area required for PV power generation. Both aspects support the transition to a society using primarily renewable energy.
A tandem solar panel consists of two solar cells on top of each other. In this case the top cell, a so-called perovskite cell, converts part of the solar spectrum in electricity and transmits the infrared light to the bottom silicon solar cell. The silicon bottom cell can be of the bifacial type, which means that it can also convert the diffuse light that falls on the rear side of the panel to electricity. The 4- and 2-terminal indicates whether the top and bottom cell deliver solar power separately or that, like the batteries in a flash light, the two cells are also electrically stacked. These are the two main configurations for tandem PV modules and are suitable for different applications and provide different manufacturing opportunities.
The international technology roadmap for photovoltaics (ITRPV) foresees that tandem PV based on crystalline silicon (c-Si) will make rapid progress towards industrial implementation, and will have obtained a significant market share by 2025. Because of the limited available area for ground PV installation and importance of rooftop PV, tandem PV is very suitable for the Netherlands.
Technologies using tandem pv
Hybrid organic-inorganic perovskite thin film solar cells are the primary candidate technology to be paired with c-Si to construct the tandem, while other candidates are also under investigation. Within the Solliance cooperation TNO executes an industrial research program on perovskite PV technology. TNO, together with academic and industrial partners, combines the perovskite thin film technology with c-Si technology to create tandem solar cells and modules.
So far, an efficiency gain of 5 percentage points over typical industrial c-Si cells was achieved. In addition, a power density of over 3300W/m2 have been demonstrated with bifacial PV tandem cells. TNO began scaled-up tandem module outdoor tests in 2018 and also develops into fully thin-film-based PV tandem technologies, such as perovskite combined with CIGS or perovskite-perovskite tandem.
CO-OPERATION WITH PARTNERS
Based on its know-how spanning the entire production chain from silicon wafers to solar cell and to PV system, TNO can provide support and cooperation on topics such as:
- Adaptation of c-Si cell and module technology to suit tandem application. Examples are specific applications of polySi passivated contact cell technology developed by TNO (also known as industrial TOPCon), and back contact cell and conductive back sheet module technologies.
- Development of high efficiency, thin film perovskite solar cells for application as top solar cell with a broad selection of transparent, thin layers for electrical conductivity.
- Scale up of the fabrication processes of perovskite solar cells and materials for industrial production within research program partnership, demonstration projects and feasibility studies.
- Integration of thin film solar cells, particular the perovskite solar cell into tandem modules. Examples are module materials suitable to protect the perovskite solar cells, and design and configuration of the electrical interconnection of the cells.
- Integral tandem device design, characterization, modeling, and optimization. For example, optical analysis and optimization for achieving high efficiencies.
- Accelerated degradation testing, including analysis of and solutions for extending the stability of these solar panels get damaged. Perovskite solar cells require interconnection and encapsulation methods different from standard c-Si technologies. Creating stable long-lifetime tandem modules is an important objective of TNO's research program.
- Monitoring of the performance of the tandem panels by collecting reliable data from field tests, leading to insight into the energy yield.
Would you like to know more?
Please contact Gianluca Coletti for more on PV Tandem Technology and its application ›