A wee bit thicker coating of perovskite film can increase the working life of a solar cell significantly, claim a team of scientists from the Okinawa Institute of Science and Technology Graduate University (OIST) that conducted such research in collaboration with Prof Shengzhong Liu from China's Shaanxi Normal University.
Using coated transparent conductive substrates with perovskite films, the team worked out a new method of fabrication for low-cost high-efficiency solar cells. They applied a gas-solid reaction-based technique wherein the substrate is coated with a layer of hydrogen lead tri-iodide incorporated with a small amount of chlorine ions and methylamine gas. This process, said the team, allows for larger uniform panels, each consisting of multiple solar cells.
"The solar cells are almost unchanged after working for 800 hours," said Dr. Zonghao Liu, a postdoctoral scholar at OIST and the first author of the study. "The thicker absorber layer ensures good reproducibility of solar cell fabrication, which is a key advantage for mass manufacturing in the realistic industrial-scale setting."
According to the researchers, this method produces perovskite solar cells with an efficiency comparable to crystalline silicon cells, at much cheaper cost than silicon solar cells.
A 'generous' grant from the OIST's Technology Development and Innovation Center has helped it build a working model of their new perovskite solar modules consisting of multiple solar cells on 5 cm x 5 cm substrates with an active area of 12 cm2. This process of upscaling from the 0.1 mm2 sized prototype has brought down the efficiency to 15% from 20%, but it is part of the challenge of increasing the size of their newly designed solar cell to large commercial-sized panels several feet long. For this, the scientists look forward to industry support.
"There exists a large gap between the findings in lab and reality, and the industry is not always ready to cover this entire gap by itself. So, the researchers need to take one more necessary step beyond their labs and meet the industry half-way," said Prof. Yabing Qi from Energy Materials and Surface Sciences Unit at OIST.
Findings of their research have been published in Nature Communications journal.