IISC Current Affairs - 2019
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The researchers from the Indian Institute of Science (IISc), Bengaluru have developed a cost-effective, high-performance, self-powered UV photodetector.
The self-powered UV photodetector can use the harvested optical energy for direct self-charging of energy storage devices such as supercapacitor. It can also be used for operating electronic devices in the absence of external power source.
What is Photodetector?
Photodector is a device capable of sensing (detecting) or responding to electromagnetic energy, typically light by using the electrical effect of individual photons.
What researchers have developed?
- The researchers have developed the photodetector by integrating semiconducting vanadium doped zinc oxide (VZnO) nanoflakes with a conducting polymer.
- The zinc oxide (ZnO) is the base material for UV detection which can be doped with vanadium to produce photodetectors that are self-powered.
- The photodetector has superior performance in terms of faster detection of photo signals in the order of milliseconds even when UV light intensity is low.
How it works?
- When doped with vanadium, the microstructure of ZnO changes from nanorods to closely-packed nanoflakes. It causes increase in the surface area to the volume of the material.
- It also creates surface defects within the band gap of ZnO, which helps in trapping the UV radiation that falls on the nanoflakes.
- These nanorods are one-dimensional and cause more light reflection from top surface. When UV light enters into pores it undergoes multiple reflections and finally gets absorbed.
What are potential benefits?
- The nanoflake (VZnO) produces five times more photocurrent, compared with ZnO, which generates only 40 nA photocurrent.
- Once these nanoflakes are hydrogenated, the current generation capacity further increased to 1,000 nA.
- When these hydrogenated nanoflakes exposed to UV light, they detect photo signal within milliseconds, which is nearly 100 times faster than conventional UV photodetectors.
- VZnO nanoflakes structure has 98% light harvesting efficiency which is much higher than 84% seen in ZnO.
The Indian Institute of Sciences (IISc), Bangaluru was adjudged as the best Indian university in the first National Institutional Ranking Framework (NIRF).
NIRF Survey was the first of its kind of indigenous ranking framework for higher education institutions in the country. It was launched by the Union Ministry of Human Resource Development in September 2015.
It outlines a methodology to rank institutions across the country based on the parameters broadly covering Teaching, Learning and Resources, Research and Professional practices, Graduation Outcomes, Outreach and inclusivity and Perception.
The NIRF ranking covers six categories of institutions including universities, engineering, management, pharmacy, architecture and colleges.
Top 5 universities
- Indian Institute of Science, Bangalore (Score: 91.81)
- Institute of Chemical Technology, Mumbai (87.58)
- Jawaharlal Nehru University, New Delhi (86.45)
- University of Hyderabad, Hyderabad (85.45)
- Tezpur University, Tezpur, Assam (84.31)
Top 5 management institutes
- Indian Institute of Management, Bangalore (Score: 93.04)
- Indian Institute of Management, Ahmedabad (89.1)
- Indian Institute of Management, Calcutta (87.45)
- Indian Institute of Management, Lucknow (86.12)
- Indian Institute of Management, Udaipur (84.22)
Top 5 engineering institutes
- Indian Institute of Technology, Madras (Score: 89.41)
- Indian Institute of Technology, Bombay (87.66)
- Indian Institute of Technology, Kharagpur (83.91)
- Indian Institute of Technology, Delhi (82.02)
- Indian Institute of Technology, Kanpur (81.07)
Top 5 Pharmacy Institutions
- Manipal College of Pharmaceutical Sciences, Manipal
- University Institute of Pharmaceutical Sciences, Chandigarh
- Jamia Hamdard, New Delhi
- Poona College of Pharmacy, Pune
- Institute of Pharmacy, Nirma University, Ahmedabad