Water is the secret ingredient in a basic method for making critical components for solar cells, X-ray detectors, and other optoelectronic devices.
Perovskites, an interesting and adaptable nanomaterial with a crystal structure, could be used to create the next generation of photovoltaics, semiconductors, and LEDs. Perovskites have already demonstrated equivalent efficiency as silicon, are less expensive to produce, and have a configurable bandgap, which means the amount of energy they can absorb, reflect, or transmit may be adjusted to suit different applications.
Water is normally kept as far away from the perovskites-making process as feasible. Moisture can cause faults in materials, making them fall apart more quickly when utilised in a device. That’s why perovskites for scientific research are frequently produced by spin coating in a nitrogen glove box.
Members of the ARC Centre of Excellence in Exciton Science have now discovered a straightforward technique to use water as a positive factor to influence the formation of phase-pure perovskite crystals. Because this liquid-based system operates at room temperature, it is cost-effective. The team, led by Monash University academics, discovered that by altering the water-to-solvent ratio during the early stages of the process, they could pick between distinct forms of perovskite crystals with varying shapes.
Corresponding author Dr. Wenxin Mao of Monash University said, “By carefully tuning the concentration of water in the precursor solution, we realized the precise control of particular perovskite phases.” The coordination of lead and bromide ions in the precursor solution was shown to be a key component in deciding which types of crystals develop, according to computational and thermodynamic analyses undertaken by colleagues at the University of Sydney.
Lead author Qingdong Lin, a Ph.D. student at Monash University, said, “We now understand the internal mechanics and function of water inside the precursor solution. By doing that we can further use water to control the crystallization process.”
Crystals made using this method were combined with back-contact electrodes using nanofabrication to make X-ray detection devices to demonstrate the quality of the ultimate result. This test sample outperformed prototype perovskite X-ray detectors built using slower, more complicated fabrication procedures, and performed similarly to commercial X-ray detectors now in use in real-world contexts, such as medical imaging and Geiger counters.
Wenxin said, “We compared them with commercial X-ray detectors as well as other types of perovskites and we do have a very good responsivity and sensitivity to X-rays. Overall this project shows that we have found a smart way to control inorganic perovskite single crystals. “The methodology is flexible and feasible and doesn’t require a very unique environment or technique to apply it.” Perovskites made using this technology could be used in UV light detection, lasers, and solar concentrators, in addition to solar cells, X-ray detectors, and LEDs.
Read the entire study here.