Periodic Reporting for period 1 - APERITIF (Dry-processing of metal halide perovskites into thin films)
Reporting period: 2023-11-01 to 2025-04-30
Demand for photovoltaic panels has surged in the past year, driven by the Green Transition, the Green Deal, and various other initiatives that have increased interest and adoption rates. Today most solar cells are based on silicon semiconductors that are reaching their theoretical limit in sunlight to electricity conversion efficiency. Perovskite semiconductors are a promising upgrade to photovoltaics. When perovskite semiconductors are added to silicon semiconductors it increases the power conversion efficiency from the solar cells from 26 to 36 %. Such an increase in efficiency leads to an important further decrease of the cost of electricity. Currently, there is no reliable, scalable, fast and economic method to deposit perovskite semiconductors on Silicon wafers. This is in part because the surface of the Silicon in a solar cell is not flat but has micrometer size pyramids that are needed to increase the absorption of sunlight (see Figure 1a). In the ERC funded Advanced Grant “HELD” we have developed a deposition process that is completely solvent free, compatible with a wide range of perovskite precursors, operates at moderate vacuum levels, leads to high quality perovskite films and conformably coats the pyramids of the Silicon solar cells (Figure 1b). The objective of the ERC-funded APERITIF project is to increase the size of the lab-scale tool from 9 to 96 cm2 and demonstrate the uniformity and repeatability of the deposition process. After demonstrating that the process works at these larger scales for different perovskite composition, the objective is to attract equipment manufacturers, and solar cell panel producers, with the goal of licensing this process and scaling up to an industrial size prototype as the intermediate step to large scale deployment to the photovoltaic production industry.
A larger area custom made deposition tool was developed with an active area of 96 cm2. Some adjustments of the source design were needed to ensure continuous thermal contact between the heaters and the perovskite precursor material. With this adjustment, we demonstrated that the precursor material consumption per sublimation is very small and as a result the source can be used for many consecutive perovskite depositions. The perovskite conversion speed can be adjusted by the source and substrate temperature and we reached deposition speeds of 500 nm in 5 min. The process is started by lowering the pressure to 1 mbar and ended by going to atmospheric pressure. This enables accurate control of the deposition time.
By changing the inorganic precursor on the substrate and the organic precursor in the source, a wide range of perovskites with bandgaps from 1.54 to 1.72 eV have been prepared. All these perovskite films exhibit large grains (4-500 nm) and have a strong absorption up to the bandgap.
We integrated the lower bandgap perovskite in single junction solar cells which led to devices with a power conversion efficiency of 18 % on average. The solar cell performance was independent on the position of the substrate in the 96 cm2 are tool, demonstrating a high uniformity of the deposition.
By changing the inorganic precursor on the substrate and the organic precursor in the source, a wide range of perovskites with bandgaps from 1.54 to 1.72 eV have been prepared. All these perovskite films exhibit large grains (4-500 nm) and have a strong absorption up to the bandgap.
We integrated the lower bandgap perovskite in single junction solar cells which led to devices with a power conversion efficiency of 18 % on average. The solar cell performance was independent on the position of the substrate in the 96 cm2 are tool, demonstrating a high uniformity of the deposition.
The high quality of the perovskite prepared with this process is demonstrated by the exceptional stable single junction solar cells. When the solar cells were maintained at their maximum power generating conditions under 1 sun equivalent illumination at 75 degrees Celsius for 1000 hours they maintained 95 % of their initial efficiency. These are among the best accelerated (high temperature) stabilities obtained for perovskite solar cells. Using a wider bandgap (1.68 eV) first perovskite-silicon tandem cells were obtained with a power conversion efficiency of 24 % on fully textured industrially prepared Czochralski grown Silicon heterojunction cells.
To achieve further uptake and success of the outcome of the APERITIF project the following activities are needed.
I. License our knowhow to an equipment manufacturer either already supplying to the PV industry and/or in conjunction with a PV cell and module manufacturer. This will provide the market needs and knowhow.
II. As the step from a 96 cm2 lab scale tool and a process at TRL =4 to production ready equipment is a large one, further financial support either on European or National level is needed to bring this to a TRL of 5 to 6 at an intermediate size tool compatible with industrial scale compliance.
We are discussing with a European equipment manufacturer and PV panel producer to develop a pre-industrial scale tool.
To achieve further uptake and success of the outcome of the APERITIF project the following activities are needed.
I. License our knowhow to an equipment manufacturer either already supplying to the PV industry and/or in conjunction with a PV cell and module manufacturer. This will provide the market needs and knowhow.
II. As the step from a 96 cm2 lab scale tool and a process at TRL =4 to production ready equipment is a large one, further financial support either on European or National level is needed to bring this to a TRL of 5 to 6 at an intermediate size tool compatible with industrial scale compliance.
We are discussing with a European equipment manufacturer and PV panel producer to develop a pre-industrial scale tool.