Periodic Reporting for period 1 - SHERPA (Self-healing screen-printed perovskite photovoltaics beyond Shockley–Queisser Limit)
Berichtszeitraum: 2022-10-03 bis 2025-07-02
Context and overall objectives
Solar energy is central to Europe’s transition towards a clean and independent energy system. Perovskite solar cells (PSCs) are among the most promising photovoltaic technologies due to their low cost and high efficiency. However, two main barriers prevent their widespread use: instability under real operating conditions and the risk of toxic lead leakage, which is restricted under the EU’s RoHS directive.
The SHERPA project addressed these challenges by developing a new class of micro-concentrator perovskite devices. This architecture requires 90–99% less material than conventional designs, reduces the environmental footprint, and improves stability by embedding each cell into a micro-patterned structure. In parallel, it creates the possibility to surpass the Shockley–Queisser efficiency limit, thereby maximising the potential of perovskite photovoltaics for Europe’s energy future.
Work performed and main results
Over its 33-month duration, SHERPA combined advanced fabrication, characterisation and simulation:
New device architectures were fabricated using laser micro-patterning, enabling highly transparent and semi-transparent cells suitable for building integration.
Detailed electrical and optical testing confirmed stable performance under concentrated sunlight, with efficiency increases beyond those of conventional perovskite devices.
Long-term stability measurements showed slower degradation rates, while lead release remained at or below detection limits, ensuring compliance with European safety standards.
Predictive models were developed to link geometry with thermal and optical behaviour, providing design rules for future applications.
The project trained the researcher in advanced laboratory skills (XRD, SEM, ultrafast laser processing, spectroscopy) and fostered knowledge transfer through collaborations with the University of Genoa, University of Rome Tor Vergata, CNR Rome, and international partners.
Progress beyond the state of the art
SHERPA introduced, for the first time, the concept of micro-concentration into perovskite photovoltaics. Unlike conventional planar devices, this design combines high optical gain with material savings and environmental safety. The approach moves the field beyond incremental efficiency improvements and opens a new research direction towards transparent, safe, and high-efficiency solar modules.
Impact for Europe and society
The results of SHERPA contribute directly to EU policy objectives:
Supporting the European Green Deal by enabling scalable, cost-effective renewable energy.
Ensuring compliance with environmental legislation (RoHS) through reduced and safer lead content.
Advancing Building Integrated Photovoltaics (BIPV) by demonstrating transparent and lightweight modules.
Contributing to the MSCA mission of training skilled, independent researchers, able to transfer knowledge across borders and inspire future generations.
The project’s visibility was amplified through presentations at leading conferences (HOPV, EU PVSEC, PVSPACE), a feature in PV Magazine, and outreach via the EU’s ShareMyStory initiative. By combining technical advances with communication to both scientific and public audiences, SHERPA demonstrated how EU research investment translates into innovation, sustainability, and societal benefit.
Solar energy is central to Europe’s transition towards a clean and independent energy system. Perovskite solar cells (PSCs) are among the most promising photovoltaic technologies due to their low cost and high efficiency. However, two main barriers prevent their widespread use: instability under real operating conditions and the risk of toxic lead leakage, which is restricted under the EU’s RoHS directive.
The SHERPA project addressed these challenges by developing a new class of micro-concentrator perovskite devices. This architecture requires 90–99% less material than conventional designs, reduces the environmental footprint, and improves stability by embedding each cell into a micro-patterned structure. In parallel, it creates the possibility to surpass the Shockley–Queisser efficiency limit, thereby maximising the potential of perovskite photovoltaics for Europe’s energy future.
Work performed and main results
Over its 33-month duration, SHERPA combined advanced fabrication, characterisation and simulation:
New device architectures were fabricated using laser micro-patterning, enabling highly transparent and semi-transparent cells suitable for building integration.
Detailed electrical and optical testing confirmed stable performance under concentrated sunlight, with efficiency increases beyond those of conventional perovskite devices.
Long-term stability measurements showed slower degradation rates, while lead release remained at or below detection limits, ensuring compliance with European safety standards.
Predictive models were developed to link geometry with thermal and optical behaviour, providing design rules for future applications.
The project trained the researcher in advanced laboratory skills (XRD, SEM, ultrafast laser processing, spectroscopy) and fostered knowledge transfer through collaborations with the University of Genoa, University of Rome Tor Vergata, CNR Rome, and international partners.
Progress beyond the state of the art
SHERPA introduced, for the first time, the concept of micro-concentration into perovskite photovoltaics. Unlike conventional planar devices, this design combines high optical gain with material savings and environmental safety. The approach moves the field beyond incremental efficiency improvements and opens a new research direction towards transparent, safe, and high-efficiency solar modules.
Impact for Europe and society
The results of SHERPA contribute directly to EU policy objectives:
Supporting the European Green Deal by enabling scalable, cost-effective renewable energy.
Ensuring compliance with environmental legislation (RoHS) through reduced and safer lead content.
Advancing Building Integrated Photovoltaics (BIPV) by demonstrating transparent and lightweight modules.
Contributing to the MSCA mission of training skilled, independent researchers, able to transfer knowledge across borders and inspire future generations.
The project’s visibility was amplified through presentations at leading conferences (HOPV, EU PVSEC, PVSPACE), a feature in PV Magazine, and outreach via the EU’s ShareMyStory initiative. By combining technical advances with communication to both scientific and public audiences, SHERPA demonstrated how EU research investment translates into innovation, sustainability, and societal benefit.
During the 33 months of the SHERPA project, a complete workflow was developed to design, fabricate, characterise and model novel micro-concentrator perovskite solar cells (μ-PSCs).
Fabrication began with establishing a reproducible architecture of ITO/SnO2/FAPbI₃/PEAI/Spiro-OMeTAD/Au using picosecond-laser micro-patterning. Three geometries (A06, A15 and A31) were defined with stripe widths between 100–700 µm, enabling a 90–99 % reduction in material use while maintaining electrical isolation and optical concentration.
Optoelectronic characterisation demonstrated strong correlation between design geometry and performance. Under 1 sun (no lens), patterned devices achieved PCEs of 12.4–13.2 %, comparable to the planar reference. Under concentrated illumination (10 cm lens), the best device reached 74.8 % apparent PCE (normalised 38.2 %), confirming the benefits of micro-optical concentration.
Comprehensive studies on stability and environmental impact were performed. Laser-patterned cells exhibited lower degradation constants (k2 = 0.62 vs 0.09 for reference) and reduced Pb release (Δ = –0.030 ppm in HNO₃; < 0.01 ppm in H2O2, below detection limit). These results confirm compliance with EU RoHS limits.
Complementary finite-element simulations accurately reproduced thermal–optical coupling in the devices (Tmax ≈ 300–343 K), validating the predictive model for future μ-PSC optimisation.
Overall, SHERPA delivered validated micro-structured perovskite devices combining high optical efficiency, improved stability, and environmental safety. The outcomes provide a foundation for future work on transparent and building-integrated perovskite photovoltaics within the EU Clean Energy Transition framework.
Fabrication began with establishing a reproducible architecture of ITO/SnO2/FAPbI₃/PEAI/Spiro-OMeTAD/Au using picosecond-laser micro-patterning. Three geometries (A06, A15 and A31) were defined with stripe widths between 100–700 µm, enabling a 90–99 % reduction in material use while maintaining electrical isolation and optical concentration.
Optoelectronic characterisation demonstrated strong correlation between design geometry and performance. Under 1 sun (no lens), patterned devices achieved PCEs of 12.4–13.2 %, comparable to the planar reference. Under concentrated illumination (10 cm lens), the best device reached 74.8 % apparent PCE (normalised 38.2 %), confirming the benefits of micro-optical concentration.
Comprehensive studies on stability and environmental impact were performed. Laser-patterned cells exhibited lower degradation constants (k2 = 0.62 vs 0.09 for reference) and reduced Pb release (Δ = –0.030 ppm in HNO₃; < 0.01 ppm in H2O2, below detection limit). These results confirm compliance with EU RoHS limits.
Complementary finite-element simulations accurately reproduced thermal–optical coupling in the devices (Tmax ≈ 300–343 K), validating the predictive model for future μ-PSC optimisation.
Overall, SHERPA delivered validated micro-structured perovskite devices combining high optical efficiency, improved stability, and environmental safety. The outcomes provide a foundation for future work on transparent and building-integrated perovskite photovoltaics within the EU Clean Energy Transition framework.
The SHERPA project introduced, for the first time, the micro-concentrator concept into perovskite photovoltaics.
Conventional perovskite solar cells (PSCs) are planar, material-intensive and suffer from thermal and environmental instability.
By transferring optical micro-concentration and geometrical patterning—previously developed in inorganic PV—to hybrid perovskites, SHERPA demonstrated that these challenges can be mitigated simultaneously.
The new μ-PSC design enables optical concentration without external lenses, drastically reducing the absorber material by up to 99 %, while maintaining high efficiency.
This represents a major conceptual leap compared with incremental material or compositional optimisations commonly reported in literature.
Technically, SHERPA advanced laser-based micro-structuring of PSCs with micron-scale precision, validated coupled optical–thermal FEM models for predictive design, and experimentally confirmed both improved efficiency under concentration and environmental safety through reduced Pb leakage.
The project thus provided a new technological paradigm for scalable, transparent and sustainable photovoltaics that moves the field beyond the traditional Shockley–Queisser limit and brings perovskite solar cells closer to integration in everyday environments.
Conventional perovskite solar cells (PSCs) are planar, material-intensive and suffer from thermal and environmental instability.
By transferring optical micro-concentration and geometrical patterning—previously developed in inorganic PV—to hybrid perovskites, SHERPA demonstrated that these challenges can be mitigated simultaneously.
The new μ-PSC design enables optical concentration without external lenses, drastically reducing the absorber material by up to 99 %, while maintaining high efficiency.
This represents a major conceptual leap compared with incremental material or compositional optimisations commonly reported in literature.
Technically, SHERPA advanced laser-based micro-structuring of PSCs with micron-scale precision, validated coupled optical–thermal FEM models for predictive design, and experimentally confirmed both improved efficiency under concentration and environmental safety through reduced Pb leakage.
The project thus provided a new technological paradigm for scalable, transparent and sustainable photovoltaics that moves the field beyond the traditional Shockley–Queisser limit and brings perovskite solar cells closer to integration in everyday environments.