Lead-free piezoelectric and multiferroic flexible films for nanoelectronics, energy harvesting and energy storage

Principal investigators: Elisa Mercadelli, Carmen Galassi
Involved personnel: Claudio Capiani, Carlo Baldisserri

Starting date: 2019
Duration: 24 mesi
Total funding: 11 k€
Coordinator: Floriana Rusanescu Craciun (CNR-ISM)
Consortium: CNR-ISM, CNR-ISTEC

Besides the growing efforts to improve the performance of electronic devices by the modification of synthetic methods, sintering techniques, miniaturization etc. a new challenge in electronics is the flexibility to ensure the mechanical deformation of the material. Flexible electronics, which can be bent, rolled, and stretched into different shapes, would remarkably expand the applications of modern electronic devices. A couple of approaches have been developed for this purpose, the first one consisting in the application of functional materials on flexible substrates and the second in the mixing of the active components within a polymer matrix. As the first one does not ensure truly stretchable electronics, the most successful approach is the second one, in which the flexible electronics is obtained as a combination of polymers and functional inorganic components.

The main objective of the project is to obtain flexible piezoelectric and multiferroic composites for energy harvesting and storage applications.

The design, fabrication, and control of structure at micro- and nanoscale level of such composites is a challenging task mainly due to the fact that the active components are rigid inorganic structures basically hydrophilic whereas the flexible organic polymer matrix is more hydrophobic. A good compatibility between these phases should be achieved to ensure an efficient stress transfer under dynamic loading.

Flexible composite films are prepared by different methods: a) hot-pressing of mixed powders of functional ceramic and PVDF and b) solvent casting.

CNR-ISTEC is involved in the synthesis of ferroelectric (BNBT, BCTZ) and multiferroic (ferrite + ferroelectric phase composite) powders to be used as functional components, and in the compositional, structural, dielectric, elastic and piezoelectric characterization in collaboration with CNR-ISM. On the other hand, CNR-SCITEC is involved in the preparation of polymer-based composites for storage devices. Flexible films for energy harvesting are prepared by the Serbian partner, which is involved also in the ferroelectric, impedance and magnetic characterization. The obtained flexible films are tested in prototype devices for energy harvesting made by Serbian team.

PVDF-BNBT composite film
PVDF-BNBT composite film


  • L. Pardo, A. García, K. Brebøl, E. Mercadelli, C. Galassi “Enhanced properties for ultrasonic transduction, phase transitions and thermal depoling in 0.96(Bi0.5Na0.5)TiO3-0.04BaTiO3 submicron structured ceramic”, Journal of Physics D: Applied Physics, 44 (2011) 335404
  • L. Pardo, E. Mercadelli, A. García, K. Brebøl, C. Galassi “Field-induced phase transition and relaxor character in submicron structured lead-free (Bi0.5Na0.5)0.94Ba0.06TiO3 piezoceramics at the morphotropic phase boundary” Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 58 [9] (2011) 1893-1904
  • F. Cordero, F. Craciun, F. Trequattrini, E. Mercadelli and C. Galassi “Phase transitions and phase diagram of the ferroelectric perovskite (Na0.5Bi0.5)1−xBaxTiO3 by anelastic and dielectric measurements”, Physical Review B, 81 (2010) 144124
  • E. Mercadelli, A. Sanson, C. Capiani, A. L. Costa, C. Galassi “Influence of the synthesis route on the properties of BNBT ceramics”, Processing and Application of Ceramics, 3 (2009), 73–78
  • E. Mercadelli, C. Galassi, A.L. Costa, S. Albonetti, A. Sanson “Sol-gel combustion synthesis of BNBT powders”, Journal of Sol-Gel Science and Technology, 46 (2008) 39-45