Clothes that can monitor body functions, displays that can bend and stretch, and a plastic sheet for the visually challenged, with image sensors on one side and braille on the other. These are not devices out of science fiction any more, as the field of 'flexible electronics' is advancing at a rapid pace.
The Flexible Electronics lab in IISc works towards making feasible and useful solutions using materials with low bending rigidity and elasticity as substrates for electronic devices.
Conventional electronics devices use high-grade crystalline semiconductors such as silicon, gallium arsenide, germanium etc. The materials and fabrication of electronic devices and circuits are prepared in clean rooms, under temperature or pressure conditions that are far from ambient. The performance of circuits based on these materials is very good and reliable. However, making these circuits over large areas and on any arbitrary substrate results in cost, manufacturing and reliability problems.
In contrast, the Flexible Electronics Lab headed by Assistant Professor Sanjiv Sambandan, wishes to manufacture flexible semiconductor materials using fabrication processes at close to ambient conditions. Such techniques effectively result in the materials being defective i.e. is generally not crystalline in nature, has no regular lattice structure and has inherent instability. Thus the devices have limited functionality. The big challenge then is to design rugged circuits that will function satisfactorily in spite of the inherent low performance and instability.
Research happening here can be broadly split in two areas. One team works on fundamental concepts such as identifying self assembly techniques to fabricate devices at ambient conditions, studying and modeling the behaviour of fabricated devices and how they perform under mechanical stress (eg. 10.1063/1.4900440), and finally translating this knowledge to circuit and system design (see figure showing a (a) flexible and stretchable display, and profilometry of curved surfaces using field emitters on flex, (b) circuits based on organic semiconductors on flex). The other team works on the technology translation and consumer application side. Here, the researchers find ways in which we can use flexible electronics to solve common problems for industry (eg. vibration spectrum sensing, identifying cracks on large curved surfaces) and society (eg. active braille sheets, energy harvesters). The group looks to collaborate with teams that synthesize novel materials and has had successful collaborations with the Solid State Structural Chemistry and Materials Engineering Departments at IISc.
Flexible Electronics Lab, Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore.