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Quantum dots for stable solar cells  Oct 07, 2016

Solar cells prepared with new phase-stable quantum dots offer great promise

In their quest for better ways to harness solar energy, researchers from India and USA have now developed a phase-stable, all-inorganic quantum dot based solar cell and demonstrated its potential utility in optoelectronic devices. This is of great significance to the field of solar cell research where the current best model uses an organic-inorganic hybrid material that is thermally unstable.

Abhishek Swarnkar (fifth from left) with Dr. Joey Luther’s team from NREL, USA (Photo Courtesy: Boris Chernomordik)

IISER Pune Integrated PhD scholar Abhishek Swarnkar was part of the team led by Joey Luther (NREL, USA) that carried out this work published in the latest issue of the journal Science. Mr. Swarnkar’s contribution to this advance was made possible through Bhaskara Advanced Solar Energy Fellowship, a prestigious award supported by the Government of India’s Department of Science and Technology (DST) and Indo-US Science and Technology Forum (IUSSTF).

As electrical devices that can convert light into electricity, solar cells have been sought after for decades now. The overall goal in solar cell research has been to produce low-cost, high-efficiency options, which often depend on the type of semiconducting material a solar cell is made of and the processings involved Among the front runners have been materials with perovskite structure, usually hybrid organic-inorganic lead or tin halide based materials. Even though efficient at 22%, these materials are not durable and therefore not ideal for commercialization.

In the present report, Swarnkar et al have prepared and successfully isolated phase-stable CsPbI3 perovskite quantum dots, all-inorganic in nature which makes the material stable unlike the hybrid versions. Further, the team was able to prepare a long-range charge conducting film using this material, a proof-of-principle demonstration that the material could be amenable to be used to develop an opto-electronic device.

Under ambient conditions, this perovskite quantum dot solar cell shows light to current conversion efficiency of 10.77% and an open circuit voltage (equivalent to e.m.f. of a battery) of 1.23 V. The same device can also be work as an LED with low turn-on voltage and tunable emission.

The authors on this paper (Science 354(6308):92-95) titled Quantum dot-induced phase stabilization of α-CsPbI3 perovskite for high-efficiency photovoltaics were Abhishek Swarnkar, Ashley Marshall, Erin Sanehira, Boris Chernomordik, David Moore, Jeffrey Christians, Tamoghna Chakrabarti and Joseph Luther.

- Reported by Shanti Kalipatnapu