Quantum dots have shown the future of photovoltaic materials for solar cells in many of their uses, according tomedia. Recently, researchers at Los Alamos National Laboratory (LANL) have developed a new type of quantum dot solar cell that maintains efficiency without using toxic elements found in most batteries.
It is understood that the main problem facing quantum dot solar cells is that they are made of toxic elements such as lead and cadmium. So in the new study, the LANL team experimented with a different approach, using copper, vanadium and selenium to make dots and then layering them with zinc.
These quantum dots are then embedded in the pores of titanium dioxide films. When exposed to solar radiation, quantum dots absorb photons and release electrons to the surrounding titanium dioxide to generate an electric current. Combining so many elements into quantum dots can have a significant impact on the efficiency of the device, but in this case, the team found that these defects actually improved the process of light energy conversion.
“We were pleasantly surprised by the measurements of the device,” said Victor Klimov, the study’s lead author. Despite these flaws, they show near-perfect performance in our solar cells — we detect 85 photoelectric electrons per 100 absorbed photons, which means that photon-to-electron conversion is 85% efficient. “
But the actual solar conversion of the battery is much less efficient — only about 9 percent. That’s the average for quantum dot solar cells, slightly below the world record of 16.6 percent set a few months ago. But the team’s goal is to be a non-toxic quantum dot, not to create a new efficiency record.
The team says the study shows that quantum dot solar cells are very useful in the future. In addition to the newly discovered non-toxicity, their production costs are very low and can be scaled up relatively easily.
The study was published in Nature Energy.