The work entitled “Effect of Cristallinity of Nb2O5 Electron Blocking Layer in Dye Sensitized Solar Cells” won the best poster award in the Physical Sciences section, at the 102nd Indian Science Congress (ISC) 2015. The award carries prize money of Rs.5, 000/- besides a Certificate of Merit. The conference was held at the University of Mumbai from January 3-7, 2015.
This is a collaborative work of Green Energy Lab in Amrita School of Biotechnology, Amritapuri campus, Amrita Vishwa Vidyapeetham and Department of Optoelectronics, Kerala University, Karyavattom campus, Thiruvananthapuram. The team was led by Dr. C. O. Sreekala. Mr. Suresh S., Associate Professor, Department of Electronics, Sree Ayyappa College presented the work. He is a Teacher Fellow at the Department of Optoelectronics under the guidance of Dr. Mahadevan Pillai, Dean, Faculty of Applied Science and Technology, Kerala University.
According to Dr. Sreekala, "102nd ISC- 2015 was a great experience for our Green Energy lab team as we could interact with the eminent scientists like Dr.Awadesh Kumar Rai, Dr.Murukeshan Vadakke Matham, Dr.K.P.Rajappan Nair, and Dr.J.P.Shukla."
The structural, optical and surface morphologies of Nb2O5 annealed films were studied. Their research work leads to the following conclusions:
- Film annealed at 600 degree Celsius is crystalline in the orthorhombic phase. From the existence of mixed orthorhombic and monoclinic phases in the film annealed at a temperature 900 degree Celsius, it can be seen that a complete phase evolution from orthorhombic to monoclinic starts around 900 degree Celsius. The film annealed at 1000 degree Celsius is completely monoclinic.
- The films have very high refractive index and the value increases upon annealing.
- From the surface morphology, the film in the monoclinic phase was porous in nature and not suitable as a blocking layer in DSSC.
- DSSCs with Nb2O5 blocking layers were fabricated. The structural, optical and surface morphologies of the blocking layers were studied.
- The effects of crystallinity of the blocking layer were investigated. It is seen that the efficiency of the cell improves by about 50% with crystallinity of the blocking layer.
- The blocking layer thickness also influences the cell performance and it is found that increased thickness of the blocking layer increases the current density of the DSSC.