FLEXPOLE is a PRIN-2022-funded research project dedicated to the discovery of mechanically flexible organic crystals with embedded permanent electrical fields. By combining elasticity and polar molecular organization within a single crystalline material, FLEXPOLE explores a new class of functional materials with strong potential for low-power electronics, photonics, and energy-related technologies.

The project develops unconventional crystallization strategies, including high-throughput nano-crystallization, inkjet printing, field-assisted growth, and epitaxy on polar surfaces, to access new polar polymorphs of organic molecules. Advanced synchrotron-based structural characterization and in operando mechanical, electrical, and optical measurements are used to uncover structure–property relationships.

FLEXPOLE addresses key scientific challenges at the interface of crystallography, crystal engineering, and materials science, while contributing to sustainable and energy-efficient technological solutions and providing advanced training for early-career researchers.

Scientific Motivation

Organic molecular crystals are attracting increasing attention due to their low density, chemical tunability, and potential for low-energy, sustainable technologies. However, most organic crystals are mechanically brittle and centrosymmetric, which limits their application in devices requiring mechanical compliance or non-centrosymmetric properties.

FLEXPOLE explores an emerging and still largely unexplored research direction: flexible organic crystals with a net electric dipole. Such materials are promising candidates for applications including:

• Piezoelectric and ferroelectric devices
• Photovoltaic and photodetection technologies
• Nonlinear optical systems
• Low-power, flexible, and distributed electronics

By enabling the rational discovery of polar, flexible polymorphs, FLEXPOLE aims to contribute both to fundamental crystal engineering and to pressing societal challenges related to energy efficiency, renewable energy production, and distributed information technologies.

Objectives

The main scientific objectives of FLEXPOLE are:

1. To develop uncommon and innovative crystallization techniques for small organic molecules.
2. To discover new polymorphic phases characterized by mechanical flexibility and net electric dipoles.
3. To establish structure–property relationships linking molecular packing, polarity, and elasticity.
4. To characterize mechanical, optical, and electrical properties of flexible polar crystals, both at rest and under bending stress.
5. To assess the technological potential of the developed materials for electronic, photonic, and energy-related applications.

Team and Expertise

The FLEXPOLE team is composed of 2 Research Units (R-UniTS and R-UniCH) and 1 Research Subunit (RS-Elettra), bringing together a complementary set of skills and expertise, including:

• Crystallography and synchrotron-radiation-based structural analysis
• Crystal engineering and polymorphism control
• Supramolecular chemistry
• Functional materials science

This interdisciplinary approach ensures the effective integration of synthesis, characterization, and application-oriented research.