Karl Jonas Riisnaes, The 1966 PhD Scholar

Postgraduate Researcher, EPSRC Centre for Doctoral Training in Metamaterials (XM2)

I am writing to give an update on my research which is kindly supported by the 1966 PhD scholarship. I started my research into metamaterials at the University of Exeter in September 2018. I am now close to finishing my PhD, and I plan on submitting my thesis in December. As of late, much of my research has been focused on writing up a paper where I show the use of the perovskite crystal devices I am developing in real world applications. In the paper we are showcasing a very effective way of encapsulating the fragile crystals allowing us to use them in environmental and human body sensing – specifically for water particulate measurements and blood pressure sensing. As far as we know, this is the first time perovskite crystals have been used in this way, so it’s quite exiting!

Project overview

- Establish and investigate the viability of transportation and storage of Organo-Halide Perovskite Crystals from our collaborators in Italy to our facilities in Exeter.

- Examine methods of device fabrication based on Organo-Halide Perovskite Crystals.

- Electrical contact deposition on crystal though orthogonal electron beam lithography.

- Fabrication and measurement of perovskite based Photo transistor.

- Find a viable encapsulation method.

- Showcase the technology outside the lab and in various and challenging environments.

Research progress to date

As mentioned in previous updates I have found an effective way of using electron beam lithography based methods to deposit metal electrodes on the perovskite crystals we are researching. This is a novel method within the field and enables nanometer scale devices to be fabricated with simple steps. This method improves the resolution a thousand fold compared to conventional processing methods for the perovskite crystals. Optoelectronic measurements on devices fabricated with the method shows parameters comparable and surpassing the state of the art and we are submitting this paper to a top tier journal. Sadly we recently got rejected by the journal Nature, but it was a close call and we believe we are close to publication. I am currently working on a new journal submission showing a very effective method of encapsulating the fragile perovskite crystals. The encapsulation allows for the perovskite based sensors to be taken out of the lab and used in various environments.