research

Our Mission

Research in our group covers organic and organic-inorganic hybrid photonics based on conjugated polymers, small molecules, 2D materials and nanoparticles, and its interface with biosystems. Current research area include: polymer and small molecule solar cells with different structures, incorporation of plasmonic structures to improve organic photovoltaics, organic memory devices, organic nanoelectronics, optical and electrical characterization, energy efficient white light emitting systems, reliability studies, conducting polymers for biosensors and bioelectronics In our lab we have various projects for PhD, Integrated PhD and undergraduate students. The projects involve material development, instrumentation, device fabrication and characterization, device modeling, study of optical and electrical properties.

SEmiconductor devices

Semiconductors play an important role in our day to day life. The development in semiconductors technology has enabled management of our daily activities with a touch or a word from a person. The incredible power of semiconductor technology has been unravelled in the present situation during pandemic, where we were able to conduct our daily life without much interruption. This might not be possible without the fundamental and technological understanding of semiconductors since the development of semiconductor based devices from Bell Labs in 1953. Based on current challenges and aspirations of the humanity, more understanding about semiconductors, both in the fundamental and technological aspects is needed. Hence, there is a growing need to explore new materials, concepts, phenomena and more understanding of the physics and chemistry of semiconductors.

Silicon, being the most favoured semiconductor by the academic and industrial community, is difficult to replace. But the current status is due to last seven decades of efforts to understand the fundamentals and improvisation is foundry for developing high quality silicon for technological applications. But both academic and industry is in pursuit of alternatives due to its high energy processing techniques, limitation in extending to 3D electronics and toxicity involved in waste and processing chemicals. This has resulted in the development of new materials with elements in pure state and in combination with others like solution processable organic semiconductors and perovskite materials, quantum materials, 2D materials, etc. Miniaturization of electronic components to include more functionality in small space has resulted in many challenges as far as fundamental physics and chemistry of such systems is concerned. Different electrical and optical spectroscopic techniques, microscopy, transport studies and device physics which are used to understand the working mechanism of semiconductors need much more in-depth analysis and modifications to include phenomena involved on reduction in dimensionalities.

Our group focusses on solution processable semiconductors, understanding the physics and chemistry of such systems, designing of new devices/architectures, device physics and interface engineering. Our research work is primarily directed towards the photo induced free carrier generation, recombination and optoelectronic properties of devices made using organic, organic-inorganic hybrid, 2D, nano and quantum materials. We have been fabricating and understanding the photophysics of organic and perovskite solar cells, organic light emitting diodes, organic field effect transistors, and photodetectors. For understanding the device physics, we have been using various spectroscopic techniques like impedance spectroscopy, transient photovoltage and photocurrent spectroscopies and charge extraction by a linearly increasing voltage of photo-generated carriers (photo CELIV) technique.

OUR RESEARCH

Organic Solar Cell

Organic solar cell are potential candidate for solar energy conversion due to its light weight, flexibility, low cost, solution processability, less environmental impact and potential for large area fabrication.

Perovskite Solar Cell

A perovskite solar cell (PSC) is a type of solar cell which includes a perovskite-structured compound, most commonly a hybrid organic-inorganic lead or tin halide-based material as the light-harvesting active layer.

Photodetectors

The peculiarities of organic semiconductors make them attractive for various, innovative and disruptive optoelectronic applications. They can be tuned to absorb light from UV to near-IR using molecular engineering.

Light Emitting Diodes

An organic light-emitting diode (OLED), is a light emitting diode in which the emissive flourescent layer is a film of organic compound that emits light in response to an applied electric current.

Two-Dimensional Materials

In materials science, the term two-dimensional materials refers to crystalline solids consisting of a single layer of atoms. These materials are promising candidates especially for photodetection applications.

Field Effect Transistors

Organic field-effect transistors (OFETs) are basic elements for organic electronic circuits and provide information on charge transport properties of π-conjugated oligomers and polymers

PROJECTS

Ongoing projects

1. Integration of 2D materials in organic and organic-inorganic hybrid solar cells: Insights into charge extraction and transport

  • Funding Agency (or Internal funding) – STARS IISC
  • Duration: 2019 – 2022
  • Total project cost – Rs. 49,21,000/-

2. Transparent solar cells: A perspective for bifacial solar cells

  • Funding Agency (or Internal funding) – DST-SERB
  • Duration: 2022 – 2025
  • Total project cost – Rs. 78,51,000/-

3. Collaborative Research for Accelerated Development of Materials & devices for Energy harvesting and conservation Technologies

  • Funding Agency (or Internal funding) – DST IC-MAP
  • Duration: 2022 – 2025
  • Total project cost – Rs. 69,59,000/-
 

Completed projects

1. Approches to improve Approaches to improve open circuit voltage and fill factor – enhancing the power conversion efficiency in organic and organic-inorganic hybrid systems

  • Funding Agency (or Internal funding) – DST SERI
  • Duration: 17.05.2017- 30.08.2020
  • Total project cost – Rs. 88,34,760/-
  • Executive summary: The proposed project focused on understanding the photophysics and electrical properties of conjugated polymers and organic materials that include small molecules and polymers which are solution processed to improve the photovoltaic performance based on such systems. This involves, material development, engineering and device fabrication techniques, fundamental and device physics aspects of a solution processed semiconducting material and modeling the system.  The uniqueness of the project is in improving the open circuit voltage (Voc) and fill factor (FF) by understanding the transport properties of the devices. Effect of charge transport on Voc and FF and there by modifying the structures to obtain power conversion efficiency of >10% in organic solar cells and >15% in perovskite based solar cell is under investigation. Application of different device structures, modification of interfacial layers, tandem structure, plasmonic structure and bulk heterojunction concepts in perovskite and devices of large area 1cm × 1cm is proposed.

2.Incorporation of plasmonic structures to improve organic photovoltaics

  • Funding Agency (or Internal funding) – DST SERI
  • Duration: 01.04.2012 – 31.03.2015
  • Total project cost – Rs. 1,83,73,600/-
  • Executive summary: In this project, plasmonic solar cell by incorporating Au nanoparticles in the P3HT: PCBM active layer was fabricated using ZnO as electron transport layer and obtained an efficiency of 5.36 %. An overall highest efficiency obtained was 10.9% with PTB7: PCBM as active material, for which the device fabrication was carried in the ambient atmosphere. Squaraine based inverted solar cell was fabricated with an efficiency of 4.12 %. Perovskite based solar cell showed an efficiency of 5.67 %.

Research Area

  1. Organic bulk heterojunction devices
  2. Organic multilayered devices
  3. Organic-inorganic hybrid devices
  4. Application of 2D materials for photovoltaic application

Our Core Values

  • Electroluminescence properties of Organic and organic-inorganic hybrid structures.
  • Optical and electrical properties of field effect transistors.
  • Optical and electrical properties of nanocomposites, conducting polymers.
  • Effect of plasmonic structures on the photovoltaic efficiency and optoelectronic properties.
  • Memory devices using organic and nanocomposites.
  • Photocurrent spectroscopy of 2D materials
  • CELIV and Photo CELIV studies of organic semiconductors
  • Transient spectroscopy