The photo is sourced from pv-magazine.com
The authors of the study opted not to use polyethylene naphthalate (PEN, a polyester made from ethylene glycol and dicarboxylic acid) as a substrate material, instead using polyethylene terephthalate (PET), which is more resistant to ultraviolet radiation and is six times more cost-efficient. In addition to the PET substrate, the cell included a few other layers. The first layer consisted of indium-tin oxide, a semiconductor material that is transparent to visible light but is also capable of reflecting infrared radiation. Next was the electron transport layer made of tin oxide, a compound of tin and oxygen that looks like a black powder. It was followed by layers of perovskite absorber and tetrabutylammonium bromide (TBAB), a white crystalline powder that helped minimise defects when the perovskite was bent. Finally, the last layers were the hole transport layer responsible for the transfer of electrons from the cathode to the anode and the upper electrode made of gold.
After assembling the cell, the scientists conducted tests, in which perovskite showed an efficiency of 32.5%, whereas the efficiency of converting solar energy into electricity ranges between 20% and 25% in most cases. Even after 1,000 bending cycles, the newly-designed cell retained 80% of its original efficiency. The authors of the study estimate that the new perovskite will last approximately 40% longer than most flexible solar panels.
If successfully commercialised, this solution will help introduce photovoltaic cells into everyday life. Previously, Exeger started using a different type of flexible solar panel, Graetzel cells, to produce wireless closed-back headphones. The role of the power generator in these cells is played by a plate that is placed on the rim and powered by artificial light. When exposed to shade, the device can work smoothly for 80 hours. At the same time, Exeger plans to supply its in-house technology to manufacturers of trackers, portable speakers and remote controls.
