A variety of perovskite compositions and architectures has been evaluated. This has resulted in the best power conversion efficiency (PCE) of 23.8%, on cell area of 1cm2. This is one of the highest reported PCEs on this cell area, since other record efficiency numbers are typically on cell area like 10 times smaller.
Gradual development of large area deposition processes including blade and slot die coating for the perovskite photo-active layer as well as transport layers and electrode materials has been performed, resulting in full modules processed up to 10x10cm2, 20x20cm2 and even up to 35x35cm2. The former ones have achieved PCEs over 20%, the latter ones lag a bit behind still on the PCE value, with best obtained result of 13%.
Similarly, a variety of devices, both cells and mini-modules, have been evaluated under long term stress factors like temperature, light and humidity. With highly stable perovskite compositions and modifications on the transport layers, or use of metal-free electrodes, stable PCE beyond even 1000hrs under these conditions and especially at elevated temperature of 60 or 85C has been proven. In combination with appropriate edge sealing and/or lamination foils, several cell and module architectures have proven to sustain the lab testing conditions at 85C and 85% RH. However, combined stress testing including for example light soaking or continuous operation under maximum power point (MPP) conditions showed that the overall degradation mechanisms become much more complex and synergistic effects could occur. More effort is clearly needed to show its viability for > 20 years, and more specifically that new test protocols beyond currently used IEC standards are to be developed to make validation based on accelerated testing possible.
Operational lifetime is an important parameter in LCoE calculations, so clearly some assumptions needed to be made for that part of such calculations. Nevertheless, a full investigation of the perovskite module production process was made based on the developments within ESPResSO to fabricate the BIPV façade element containing eight 35 x 35 cm² modules. A value for the levelized cost of electricity of ≤ 0.05€/kWh could indeed be extracted from this study when this PV system would be operating in locations in Southern Europe. This analysis has not only set the boundary conditions for the minimal efficiency and operational lifetime to reach this cost target, but also on what process throughput, module sizes, cost distribution of materials and production etc should be considered.
Especially extending this analysis with a prospective view how the environmental product footprint could impact the European energy mix in coming decades was shown to be very fruitful. This analysis emphasized that perovskite PV technology could have a substantial effect on reducing the CO2 footprint of the European energy mix when deployment would occur in the timeframe of 2030-2040, with high emphasis on BIPV application.
