Roadmap 2
Perovskite PV modules
Rationale for support
Europe is the leader of perovskite-PV as the most promis- ing emerging PV technology as well as multi-junction ap- proaches (see Roadmap 4).
Metal halide perovskite-based PV (‘perovskite-PV’ or ‘Pk- PV’ for short) has been the subject of research in the last decade having the advantage of
- use of abundant materials together
- low material and energy usage
- potential low-cost and high-speed production meth- ods
As a thin film PV technology, Pk-PV can be produced on different “passive” substrates like glass (rigid or flexible), or foils, or another solar cell in the case of multijunction mod- ules. Any form of Pk-PV cell is easy to layer on top of and connect to another cell. Pk-PV can be produced in opaque or transparent or anything in between, making it highly versatile PV technology.
Status
Industrial activity
Several companies are currently setting up pilot produc- tion lines in Europe (5), (6), Evolar is focusing on semi-trans- parent perovskite on glass as an upgrade for existing PV modules like cSi or CIGS with the 4-terminal approach, where current PV module top glass can be replaced by a glass containing the semi-transparent Pk-PV module. Saule Technologies is focusing on flexible Pk-PV made by ink jet printing, with sheet-to-sheet processes today, but with the intention to move to roll-to-roll production. Solaronix’ pilot line produces currently opaque Pk-PV on glass. In China, meanwhile, GCL New Energy is producing semi-transpar- ent and hence bifacial perovskite modules with non-certi- fied efficiencies of 16 % on 40 x 60 cm2 glass on a 10 MW line that will soon be joined by a 100 MW pilot line. The company has plans for a 1 GW production line in 2022.
Efficiencies
Pk-PV’s power conversion efficiency in a single-junction architecture has increased from 3.8 % at its discovery in 2009 to an impressive 25.5 % in 2020. With that, Pk-PV has joined three other PV technologies (cSi, GaAs and GaInP) in reaching at least 75 % of their Shockley-Queisser per- formance limits. A module efficiency record of 17.9 % was achieved in 2020 by Panasonic on an aperture area of over 800 cm2.
Scalable processes have been adopted for the various deposition methods for the perovskite absorber layer as well. (7) Successful demonstrators have been produced by applying single step wet deposition by coating or printing of the perovskite precursors, followed by a quenching step. Also, single-step precursors co-evaporation have yielded highly efficient perovskite absorber layers. Several groups are also investigating the dual step approach, where first a single layer of one of the precursors is applied by wet dep- osition or (co-)evaporation, followed by the deposition of the other precursors by wet deposition.
Stability
Early Pk-PV had poor stability but it has improved. (8) By se- lecting the right device architectures, materials and pro- cesses, several companies and research organisations can now make modules meeting one or more stress test stand- ards (IEC 61215).
Lead
The best performing Pk-PV single-junction modules today contain a small amount (0.3-0.6 g/m2) of lead. Although the total amount of lead in the modules is low, the lead is quite mobile and there is therefore a risk of leakage into the environment. For this reason, research is ongoing into the use of lead-free perovskite materials as well as into ways of ensuring that the lead cannot escape from the modules.
The long-term final vision for perovskite-only PV technologies is that they will be produced at very low costs, will ultimately be highly efficient and stable and in common with other non-Pk-PV technologies could be made into a very broad scope of different embodiments: flexible or rigid, opaque or semi-transparent or translucent.
Targets, Type of Activity and TRL
In case of single junction Pk-PV, it is expected that mod- ule efficiencies will be comparable to current existing PV technologies within 5 years. Depending on the learning curve, Pk-PV module manufacturing could quickly achieve comparable costs compared to currently commercial tech- nologies.
The long-term final vision for perovskite-only PV technol- ogies is that they will be produced at very low costs, will ultimately be highly efficient and stable and in common with other non-Pk-PV technologies could be made into a very broad scope of different embodiments: flexible or rig- id, opaque or semi-transparent or translucent. This gives perovskite PV the potential to address almost all of the re- quirements for a seemingly endless list of applications in the domains of IIPV, BIPV and VIPV but also for consumer electronics and IoT applications.
Understand charge formation and charge move- ments on atomic level. This will help in further im- prove efficiency, intrinsic lifetime and material usage
Lead-free Pk-PV
Pk-PV with features to immobilize lead in case of catastrophic events
Utilise Low-cost, high performing and fast pro- cessable transparent electrodes for perovskite PV through novel materials/processes
Resolve stability issues of perovskite absorber/solar cells
Develop recycling strategies for early stages of new (thin film) PV technology
Integrate UV and IR absorbing perovskites for PV windows with transparency in the visible light range
Evaluate impact of device design (n-i-p versus p-i-n stacks) and deposition techniques on manufacturability
characterisation to enable industrial uptake through standardization
Develop industrially feasible processes and equip- ment for reliable, low cost and high throughput production of perovskite solar cells with low mate- rial usage, low energy and material consumption
Explore co-evaporation processes to ensure con- trolled and reproducible environment
Develop soft deposition processes for TCO layers to reduce damage of sensitive substrates, e.g. organic materials or perovskites
Improve surface passivation of perovskite layers
Replace toxic solvents with solvents with less health and environmental impact
Demonstrate at pilot level highly efficient and long- term stable semi-transparent and also bifacial per- ovskite PV single junction on glass for integrated Photovoltaics, later extension to hybrid 4-termi- nal applications on different cSi, CIGS and CdTe PV modules
Demonstrate at pilot level highly efficient per- ovskite PV single junction on foil by using roll-to-roll processes
Demonstrate industrial viability of perovskite tech- nology including by transferring industrial thin-film processes from CIGS and CdTe to Pk for low-cost tandem cells
European pilot line (~ 100 MW) for glass-based bi- facial Pk-PV modules with the option to extend to higher efficiency all-perovskite PV multi-junctions to demonstrate low-cost material and processes for the production of modules with high throughput, low-energy consuming processes
European pilot line for roll-to-roll bifacial Pk-PV pro- duction with the option to extend to higher efficien- cy all-perovskite PV multi-junctions to demonstrate low-cost material and processes for the production of modules that should allow to go to multi GWp production capabilities with one single roll-to-roll production line
KPIs
Our vision is that in 2030, Pk-PV will have become the thin film technology with the highest market share for roof-top and utility-scale applications. For 2030 European Pk-PV R&D should achieve the following KPIs:
| KPI | Target Value (2030) |
|---|---|
| LCoE | LCoE of Pk-PV technology should be equal to or lower than that for c-Si |
| CO2 footprint | High-performance and sustainable PV with LCoE of 25 €/MWh at medium irradiation levels of 1300 kWh/(m2a), e.g. in southern Germany for utili- ty-scale PV and <50 €/MWh for ‘Integrated Photovoltaic’ elements (4) The yield-specific CO2 footprint of Pk-PV technologies should be <80 % |
| Manufacturing and Commercialisation | Commercially available, Pk-based modules with an efficiency of >23 % |