Imperial College London

DrAlexanderGiovannitti

Faculty of Natural SciencesDepartment of Physics

Visiting Researcher
 
 
 
//

Contact

 

a.giovannitti13

 
 
//

Location

 

Royal College of ScienceSouth Kensington Campus

//

Summary

 

Polymer electrodes for electrochemical energy stroage

I am interested in the development of sustainable electrode materials based on redox-active conjugated polymers which can enable efficient transport of electronic and ionic charge carriers simultaneously. They can be charged rapidly on the time scale of seconds and does not require hazardous/flammable solvents. Polymers can be processed from solution which will allow for low-cost production of batteries.

Find out more about the research in the open-access: ArXiv

Polymer electrodesFigure 1: Solution processed polymers on FTO substrates



Bioelectronics

show research

PolymerI am interested in the development of novel mixed conductors based on conjugated polymers. The specially designed polymers have the ability to transport electronic charge carriers (electrons and/or holes) as well as ionic charge carriers (anions and/or cations). 

Over the last few years, we have developed high performing polymers for Organic Electrochemical Transistors (OECTs) with low oxidation potentials (p-type polymers: PNASJACS). We also developed a novel class of materials which have low reduction potentials in aqueous electrolytes. This enabled us to develop the first n-type OECT: Nature Communications.

Redox-reactions of the polymers in aqueous electrolytes

Figure 2: Redox-reactions of a) p-type polymer and b) n-type polymer in aqueous solutions. 


Synthesis of polymers

Figure 3: Polymer synthesis: a) monomers, b) 1 min polymerisation and c) finished polymerisation.

Ion selective materials

show research

The sensing of ions is of great importance of understanding the function of biological systems (including the human body). I developed and synthesised an optical ion sensor material for the detection of sodium or potassium ions in solution and solid state. The sensor material is based on a conjugated polymer which has a strong absorbance in the visible light. The detector unit of the polymer is a combination of an alkoxybithiophene unit and a crown ether. The alkoxybithiophene unit tends to adopt a planar structure due to sulphur-oxygen interactions, however the addition of alkali metal ions trigger the formation of a complex which twists the structure. As a result of the twist, the polymer changes the colour which can easily be detected by the human eye. The findings were published in Advanced Functional Materials in 2016 (open-access). 

Detection of sodium ions





Figure 1: Detection of sodium ions (left: colour change from purple to yellow, right colour change of the photoluminescence)