Abstract
Development of a Multicomponent Solar Energy Conversion System with Extended Spectral Collection and Improved Efficiency (MUSES). The efficient harvesting of solar energy in low-cost manufactured devices is a key tool for implementing the energy transition from fossils to renewables. A major problem limiting the conversion efficiency of PV cells is their insensitivity to the full solar spectrum, with current PV cells only utilizing a relatively small fraction (approximately 25%) of the overall solar flux. the primary objective of the MUSES project is the development of a multicomponent device for solar energy conversion based on two wavelength shifting modules (Down Converter and Up Converter) coupled to a perovskite based solar cell. Identification, design, optimization and preparation of the materials for the fabrication of the individual components (solar cells and down and up converter layers). Assembly of the components. Development of a multicomponent device for solar energy conversion based on two wavelength shifting modules (Down Converter and Up Converter) coupled to the perovskite based solar cell. The design is aimed at recovering the unexploited high- and low-energy part of the solar spectrum, thus increasing the overall conversion efficiency and the operational lifetime of the solar cell.
Results achieved
: The main objective of the MUSES project was the development of a multicomponent solar energy conversion system with extended spectral harvesting and improved conversion efficiency. This objective was successfully achieved through the close collaboration between the University of Bologna and the CNR research unit (project coordinator), leading to the integration of an optimized down-shifting (DS) layer with a metal halide perovskite (MHP) solar cell. The compatibility of the different components developed during the project was experimentally demonstrated, and the integrated device was validated under operating conditions representative of photovoltaic applications. The project followed a stepwise approach in which each component of the device was independently developed and optimized before integration into the final architecture. The metal halide perovskite solar cell was fabricated and its stability, reproducibility, and defect landscape were systematically investigated using complementary electrical and spectroscopic characterization techniques. These studies provided a detailed understanding of the electronic properties of the photovoltaic absorber and contributed to the optimization of the device architecture. The down-shifting layer, developed by the CNR unit, consists of rare-earth-doped polymer matrices designed to absorb ultraviolet radiation and re-emit photons at wavelengths more efficiently harvested by the photovoltaic absorber. This spectral-conversion approach is applicable to both silicon and perovskite photovoltaic technologies and aims to improve the utilization of the solar spectrum while mitigating the detrimental effects of high-energy UV radiation. The first stage of the integration focused on PMMA-based down-shifting films deposited on both monocrystalline silicon (c-Si) solar cells and perovskite solar cells employing a Cs₀.₁₇FA₀.₈₃Pb(I₀.₇₇Br₀.₂₃)₃ absorber. External Quantum Efficiency (EQE) and current-voltage measurements confirmed the correct operation of the luminescent layer by comparison with PMMA-only reference samples. For c-Si devices, a measurable enhancement of the EQE in the 320–375 nm spectral range demonstrated the capability of the down-shifting layer to convert ultraviolet photons into useful photocurrent. In perovskite solar cells, although optical coupling effects limited the overall enhancement, these experiments successfully validated the spectral-conversion mechanism and identified the critical aspects to be addressed in subsequent optimization. Based on these results, an improved architecture was developed in which the PMMA matrix was replaced by a PDMS matrix doped with europium complexes. The optimized layer was deposited on the illumination side of the perovskite solar cell, simultaneously acting as a protective coating and as an active spectral-conversion element. The final MUSES prototype enabled the combined evaluation of optical and electrical performance, confirming the functionality of the integrated system and the effectiveness of the europium-based down-shifting strategy under realistic operating conditions. The project achieved the main scientific and technological objectives originally proposed. In particular, it demonstrated: • the successful fabrication and optimization of stable and reproducible metal halide perovskite solar cells; • the development and validation of rare-earth-based down-shifting layers for ultraviolet spectral conversion; • the successful integration of the photovoltaic device with the optimized spectral-conversion layer into a complete multicomponent architecture; • the experimental validation of the down-shifting concept through optical and electrical characterization of the integrated device; • the identification of the main factors currently limiting device performance and of the technological solutions required to further improve conversion efficiency. The results also identified clear perspectives for future developments. In particular, further optimization of the PDMS/ITO/glass interfaces is expected to reduce optical losses due to reflection and scattering, while simplification of the device architecture—through direct deposition of the perovskite stack onto functionalized PDMS substrates or incorporation of the europium complexes into the glass substrate—could further enhance the effectiveness of the spectral-conversion strategy. Overall, the MUSES project has established a robust technological platform for the integration of spectral-conversion materials with next-generation photovoltaic devices and has generated the scientific knowledge required to support future developments toward higher-efficiency solar energy conversion systems. The activities carried out within the project have also produced significant scientific outputs, including publications, conference contributions, and the development of new collaborations, as summarized below. TESI 1) TESI di LAUREA MAGISTRALE in Physics Cavalazzi, Gianmarco (2024) Advanced materials for down-shifting of solar energy in perovskite photovoltaic cells. 2) TESI di DOTTORATO (in progress) Del Conte Corrado, Corrado Del Conte — Università di Bologna — Home Page dottorando in Nanoscienze per la medicina e per l'ambiente, UNIBO, Conference paper: 1. Radiation Hardness and Defects Activity in Perovskite Radiation Detectors” A. Ciavatti, C. Bordoni, E. Colantoni, L. Basirico, D. Cavalcoli, B. Fraboni, 2025 IEEE Nuclear Science Symposium (NSS), Medical Imaging Conference (MIC) and Room Temperature Semiconductor Detector Conference (RTSD), Yokohama, Japan, 1 – 8 Nov. 2025. 2. Corrado Del Conte, Andrea Ciavatti, Margherita Bolognesi, Marco Natali, Lorenzo Squillantini, Andrea Barbieri and Daniela Cavalcoli, “Defect studies and down conversion strategies of double-cation mixed perovskite solar cells” abstract submitted for the conference GADEST 2026, International Conference on Gettering and Defect Engineering in Semiconductor Technology Venice from September 27 to October 2, 2026. Publications: 3. A. Ciavatti, V. Foderà, G. Armaroli, L. Maserati, E. Colantoni, B. Fraboni, D. Cavalcoli, Radiation Hardness and Defects Activity in PEA2PbBr4 Single Crystals. Adv. Funct. Mater. 2024, 34, 2405291. https://doi.org/10.1002/adfm.202405291 4. C. Bordoni, L. Calcaterra, A. Ciavatti, et al. “ Linking Device Performance to Nanoscale Photoactivation of Grain Boundaries in 2D Hybrid Halide Perovskites.” Advanced Materials Technologies (2026): e00004. https://doi.org/10.1002/admt.202600004 5. Corrado Del Conte, Andrea Ciavatti, Margherita Bolognesi, Marco Natali, Lorenzo Squillantini and Daniela Cavalcoli “Investigation of Defects Activity and Environmental Degradation in Cs/FA Mixed-Halide Perovskite Solar Cells, under review in Materials Science in Semiconductor Technology, 2026.Project details
Unibo Team Leader: Daniela Cavalcoli
Unibo involved Department/s:
Dipartimento di Fisica e Astronomia "Augusto Righi"
Coordinator:
CNR - Consiglio Nazionale delle Ricerche(Italy)
Total Unibo Contribution: Euro (EUR) 78.000,00
Project Duration in months: 24
Start Date:
30/11/2023
End Date:
28/02/2026
