Joining the dots for smarter solar cells
doi:10.1038/nindia.2016.136 Published online 20 October 2016
Researchers have made stable all-inorganic quantum-dot-based solar cells that efficiently harness sunlight and convert it to electricity, making them suitable for use in a wide range of optoelectronic devices1.
Solar cells are currently made using organic-inorganic hybrid materials that are thermally unstable, reducing their efficiencies in harvesting solar energy.
Scientists from Pune-based Indian Institute of Science Education and Research and US-based National Renewable Energy Laboratory prepared thin films using surfactant-coated quantum dots made of caesium lead iodide. They then explored the films’ optical and electrical properties and potential to capture sunlight in solar cells.
The quantum dots are stable for months at ambient conditions and have tunable band gaps at visible wavelengths. The films exhibit long-range electron transport. When used in solar cells, the films showed light-to-current conversion efficiencies which exceed 10%.
The films can also be used to make light-emitting diodes with low turn-on voltage and tunable emission. Unlike their bulky counterparts, the caseium-lead-iodide-based quantum dots are stable at low temperatures, a promising feature for making various optoelectronic devices, say the researchers.
1. Swarnakar, A. et al. Quantum dot–induced phase stabilization of α-CsPbI3 perovskite for high-efficiency photovoltaics. Science. 354, 92-95 (2016) doi: 10.1126/science.aag2700