The technology behind silicon solar cells hasn’t changed much in decades, although efficiencies have been boosted with incremental improvements, such as a new coating developed at the University of Texas. Pervoskites, however, are one of the big changes in solar technology in recent years.
Perovskites are a class of materials that have received much attention due to their potential to lower the cost of solar cells. The advantage that the material has over silicon (the material used in the most common solar cells) is that it requires less electricity and industrial processing in the manufacturing process. Perovskites can be sprayed onto objects like paint, crystallizing into a thin film that can capture energy in a solar cell. Researchers are working to understand just exactly how that crystallization takes place, scale up manufacturing, as well as trying to identify alternative lead-free compositions. Read "Metal Halide Perovskites Show Promise for Solar Power".
Perovskites have a combination of good opto-electronic properties with low material and manufacturing costs, making them a suitable material for any application that involves light absorption, emission and detection. Researchers around the world are looking at perovskites to enhance a variety of light-based devices, finding that they can be used not just in good old-fashioned solar cells, but also in X-ray detectors, laser projection systems and more.
Researchers from IMO-IMOMEC, a laboratory associated with Imec, along with colleagues from KU Leuven, UGent and UAntwerpen (Belgium) are exploring what perovskites can do for X-rays. In X-ray detectors, perovskites could lead to better image quality, which could lower radiation exposure levels for humans in both medical and security screenings. Researchers have been applying perovskite layers on flexible substrates in order to make a low-cost, low-weight, robust large format and potentially flexible X-ray detector. Such detectors would have potential use for human and veterinary health applications, as well as in industry and security applications. In industry, X-ray scanners are used for non-destructive testing such as in automotive, aerospace, power generation and more. Security applications are growing due to increased global traffic and trade, and there is greater need to scan people and materials in airports, ports and border crossings.
Perovskites are also being explored for use in laser projection systems, where perovskite nanocrystals could be used as green or red gain material. This approach would reduce the complexity and cost (potentially up to a 40% cost reduction). Added benefits include the tunable bandgap and high optical gain of perovskites. For more detail on this work read “Perovskites Move Beyond Solar Cells”.
In other research, the Irish Photonic Integration Center (IPIC) is working with researchers from MIT’s Photovoltaic’s Research Laboratory on integrating small solar cells into indoor Internet of Things sensors and wearables. As the power required to operate these devices continues to increase, the potential for powering them with tiny solar cells increases. For more on this approach, read “PV Research Partnership Spans Countries, Disciplines”
Indoor solar-powered devices
MIT researchers are focusing on using perovskite cells that are thin, flexible, transparent, and can be tuned to harvest energy from any kind of indoor or outdoor lighting. One of the researchers, Sai Nithin Kantareddy, noted that the work is basically “building enhanced RFID tags using energy harvesters for a range of applications.”
In a pair of papers published in the journals Advanced Functional Materials and IEEE Sensors, the researchers describe using the sensors to continuously monitor indoor and outdoor temperatures for several days. The sensor transmitted data continuously at distances five times greater than traditional RFID tags, with no batteries required. For more on this work read, “MIT Research Develops Photovoltaic-Powered IoT Sensor”.
Written by Anne Fischer, Managing Editor, Solar Novus Today