People
Dr. Nisha Ranjan

Dr. Nisha Ranjan

Postdoctoral Researcher

Research Area A

Institute of Physical Chemistry, University of Freiburg

Cluster of Excellence livMatS @ FIT – Freiburg Center for Interactive Materials and Bioinspired Technologies

Project

Chemistry of triboelectric materials - Understanding the basic charge separation processes
The triboelectric effect describes the electrification of two similar or dissimilar materials as a result of rubbing or contact. However, the charge build-up through contacting has not gained much attention because of its adverse effects like electric shocks, short circuits, and machine failures. In this project, I look at the other side of the coin, namely the utilization of such a phenomenon to harvest energy. Therefore, the ultimate aim of my project is to understand the triboelectric effect and maximize the efficiency of triboelectric nanogenerators (TENGs) with functional materials. In my work, I use experimental techniques like Atomic Force Microscopy, Kelvin Probe Force Microscopy, X-Ray Photoelectron Spectroscopy, and Infrared spectroscopy to understand the charge generation and separation mechanisms at interfaces. This will provide deep insight into the physical origin of these charges and their manifestation at the interfaces, which will then be employed to harvest energy for the adaptive material system.

First Supervisor

Dr. Bizan N. Balzer

Project outcomes

In the project “Understanding the basic contact-separation process,” we successfully used AFM based techniques: Force Spectroscopy (FS) and Kelvin Probe Force Microscopy (KPFM) to conduct and quantify the contact-separation triboelectric experiments. First, we designed a contact-separation interface with self-assembled monolayers comprising donor-acceptor organic molecule pairs (in collaboration with Prof. Birgit Esser and Dr. Michael Walter). To synthesize and characterize the interface, we used techniques such as XRD, AFM, FTIR, XPS and DFT calculation (in collaboration with Prof. Anna Fischer, Dr. Michael Walter and Prof. Birgit Esser). Finally, we investigated the contact-separation triboelectric effect with our micro-scale triboelectrification assay using FS and KPFM. FS allowed us to steer the contact-separation parameters (load, velocity and dwell) precisely. Additionally, with our unique substrate design, we could quantify the effectiveness of the charge transfer due to the contact-separation process.

Moved on to
Position as Elisabeth Bauser Postdoctoral Fellow at Max Planck Institute For Solid State Research in 2025.

Publications at livMatS