Periodic Reporting for period 1 - VALHALLA (Perovskite solar cells with enhanced stability and applicability)
Período documentado: 2023-01-01 hasta 2024-06-30
To do so, VALHALLA is developing
- efficient perovskite (PVSK) absorbers made with methods avoiding the use of solvents, stable towards light, heat.
- Integrate these absorbers in single junction solar cells, opaque and semitransparent, using rigid and flexible substrates and with indium free electrodes.
- rigid and flexible encapsulation methods
- ·outdoor and indoor test facilities.
- accelerated lifetime test equipment will be developed using input from the outdoor test results on VALHALLA samples.
- Characterize pristine and aged devices and films with a wide range of techniques.
- Use molecular and physical modelling to identify degradation pathways and measures to overcome them.
VALHALLA will also demonstrate
·the economic viability, environmental harmlessness and social acceptance of the technology with the calculation of its lifecycle costing (LCC), environmental and social lifecycle analysis (LCA).
VALHALLA is a multidisciplinary team consisting of 12 partners from 8 European countries, 2 associate member countries and 1 widening country; 3 industrial partners & 9 Research & Technology organizations.
In WP2, partners developed all vacuum deposited single junction solar cells with power conversion efficiency reaching 21.8 % a record value as far as we know. Flexible solar cells on very thin polyetherketone was developed with a power conversion efficiency of 17 %. Semitransparent solar cells with an average visible transmittance of 50 % with a power conversion efficiency of 9.6 % were developed. We prepared semitransparent solar cells with transparent conducting electrode based on aluminium doped zinc oxide deposited using pulsed laser deposition. Detailed balance limit calculation allowed to identify limiting factors of perovskite solar cells with several bandgaps. And a newly developed analysis of impedance spectroscopy allows to obtain ionic mobility values.
In WP3 perovskite deposition using co- and sequential sublimation was achieved at areas over 100 cm2. Modules using these large area substrates were prepared using laser scribing to generate multiple cells placed in series. An effective encapsulation based on glass-glass was developed for rigid cells.
In WP4, outdoor monitoring setups were installed capable of tracking irradiance, temperature, power output simultaneously. First all vacuum processed cells were tested outdoor during 6 months without performance losses. Cells with doped hole transport layers did show degradation. Using SIMsalabim and Bayesian Optimization Tool BOAR we identified that the HTL/perovskite interface and increased trap density were the main causes for the efficiency loss. The degradation mechanism of lead iodide perovskite in presence of O2/H2O has been studied by DFT simulations. H2O preferentially removes the organic FAI moiety from the surface and O2 leads to the formation of periodates which activate the formation of PbI2 vacancies that lead to the degradation of the material. The use of molecular binder, e.g. amines, sulfonium molecules, and hydrophobic large cations, e.g. EDAI2, as passivants increases the long term stability and efficiency of the perovskites.
In WP5, the most used perovskite solar cell stacks were identified and the materials used in these stacks were compared on global warming potential.
We found that when exposed to heat (85 degrees C) and light (1 sun) perovskite containing formamidum and methylammonium were more stable than those containing cesium and formamidium.
Semitransparent solar cells with an average visible transmittance of 50 % with a power conversion efficiency of 9.6 % were developed.