Optoelectronic materials turn light into electricity; some can also turn electricity into light. My research deals with examples of these materials which have great potential for use in advanced technologies.
My team uses high-performing unconventional optoelectronic materials — such as halide perovskites or organic semiconductors — to create solar cells that more efficiently generate energy than do existing ones, or lighting or display technologies that consume less energy.
Halide perovskites are crystalline materials. The latest formulations convert sunlight into electricity as efficiently as do silicon solar cells. A perovskite solar cell can be layered on top of a silicon one, creating high-performance ‘tandem’ cells that capture more solar energy than do conventional ones, at barely any extra cost.
The photograph shows me in my fabrication laboratory at the National Centre for Photovoltaic Research and Education, part of the Indian Institute of Technology Bombay. The shiny instrument behind me, which my colleagues and I created to build our devices, is a ‘cluster tool’.
The optoelectronic materials we test are highly sensitive to ambient air, but we can assemble a device inside the tool without ever exposing it to ambient conditions. A magnetic arm moves the partly built device between four connected fabrication chambers, each dedicated to specific steps. This ensures that the ingredients used in one step don’t contaminate the next. We are transferring this technology to a local company to commercialize it.
We are using our cluster tool to develop tandem organic-light-emitting-diode (OLED) displays. The resolution of your mobile phone’s or smart watch’s display depends on pixel size. The red, green and blue components of each pixel are adjacent in the plane of a conventional screen; in tandem OLEDs, we stack them, making each pixel smaller to achieve much higher resolution.