Presentation Title

1, 5-Diaminonaphthalene, Chloranil: A Potential Ferroelectric

Faculty Mentor

Dr. Kimberley Cousins

Start Date

17-11-2018 9:45 AM

End Date

17-11-2018 10:00 AM

Location

C335

Session

Oral 2

Type of Presentation

Oral Talk

Subject Area

physical_mathematical_sciences

Abstract

Electronic waste recycling can cause local water and food supplies to be contaminated with toxic chemicals such as heavy metals and expose e-waste workers to vapors and direct contact with these toxic materials. Piezoelectric materials release electrical charge after undergoing mechanical stress and ferroelectrics are a subclass of piezoelectrics. Inorganic ferroelectric materials, such as Lead Zirconate Titanate (PZT), are used as memory in electronics due to their unique property of spontaneous polarization, measured in µC/cm. A substitution of organic ferroelectrics for traditional ones could reduce the amount heavy metals, like lead, in electronic recycling. The search for organic ferroelectrics with polarization comparable to that of traditional ferroelectrics has become an exciting field of study within the last decade.

In past research, 1,5-diaminonaphthalene p-chloranil (CANANP) was isolated as a candidate for further investigation based on the charge transfer it demonstrates. Polarization in charge transfer (CT) ferroelectrics is caused by a shift in electronic density from a donor molecule to an acceptor molecule in a dimer. Behera, et al. predicted CANANP to be weakly ferroelectric (0.06 µC/cm2) based on Berry phase calculations performed on the crystal structure and a constructed pseudo centrosymmetric structure. In this study, a computational reassessment of polarization in CANANP was completed using Berry Phase analysis of calculations performed using Vienna Ab initio Simulation Package (VASP) on the same structures used by Behera, et al. This analysis showed CANANP to have a remnant polarization of 8.23 µC/cm2.

Co-crystals of CANANP were grown for experimental analysis using piezo force microscopy (PFM). During this experimentation, CANANP showed both a piezo and ferroelectric response, as was predicted computationally.

Summary of research results to be presented

Following the documented crystallization for 1, 5-diaminonaphthalene, chloranil (CANANP) produced small, bar shaped crystals with an average surface area of about 1.5 mm2. To test for a phase change (a change in the structure of the crystal lattice), larger crystals of at least 15 mm2 we required. Several methods to increase the crystal surface area were attempted. Beginning with a large volume of saturated solution, the solution was allowed to evaporate slowly, over about two months. This produced single crystals with at least 25 mm2 surface area. A method of seeding small volumes of solution for slow evaporation over 5 days also produced larger single crystals nearing the 30 mm2 surface area range.

A computational reassessment using Berry phase calculations performed using VASP, based on structures analyzed by Behera, et al. predicted CANANP to have a remnant polarization of 8.23 µC/cm2. This predicted polarization is larger than the reported electronic ferroelectric tetrathiafulvalene, chloranil, which has an experimental remnant polarization of 6.2 µC/cm2. Experimentally CANANP has been examined using piezo force microscopy (PFM) where a piezoelectric butterfly curve and a ferroelectric hysteresis curve were observed. The large crystals we have grown are currently undergoing tests to quantify the remnant polarization for the system.

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Nov 17th, 9:45 AM Nov 17th, 10:00 AM

1, 5-Diaminonaphthalene, Chloranil: A Potential Ferroelectric

C335

Electronic waste recycling can cause local water and food supplies to be contaminated with toxic chemicals such as heavy metals and expose e-waste workers to vapors and direct contact with these toxic materials. Piezoelectric materials release electrical charge after undergoing mechanical stress and ferroelectrics are a subclass of piezoelectrics. Inorganic ferroelectric materials, such as Lead Zirconate Titanate (PZT), are used as memory in electronics due to their unique property of spontaneous polarization, measured in µC/cm. A substitution of organic ferroelectrics for traditional ones could reduce the amount heavy metals, like lead, in electronic recycling. The search for organic ferroelectrics with polarization comparable to that of traditional ferroelectrics has become an exciting field of study within the last decade.

In past research, 1,5-diaminonaphthalene p-chloranil (CANANP) was isolated as a candidate for further investigation based on the charge transfer it demonstrates. Polarization in charge transfer (CT) ferroelectrics is caused by a shift in electronic density from a donor molecule to an acceptor molecule in a dimer. Behera, et al. predicted CANANP to be weakly ferroelectric (0.06 µC/cm2) based on Berry phase calculations performed on the crystal structure and a constructed pseudo centrosymmetric structure. In this study, a computational reassessment of polarization in CANANP was completed using Berry Phase analysis of calculations performed using Vienna Ab initio Simulation Package (VASP) on the same structures used by Behera, et al. This analysis showed CANANP to have a remnant polarization of 8.23 µC/cm2.

Co-crystals of CANANP were grown for experimental analysis using piezo force microscopy (PFM). During this experimentation, CANANP showed both a piezo and ferroelectric response, as was predicted computationally.