Lead-free

A Research Group led by Prof. Eva Unger at Helmholtz Zentrum Berlin (HZB), in collaboration with the Indian Institute of Technology Bombay and University of Jammu, has reported the use of inkjet printing to fabricate thin films of combinatorial mixed formamidinium tin-lead perovskites and evaluated their layer quality and device performance. The team focused on optimizing the inkjet-printing process to ensure precise film deposition and enhance device performance.

Image credit: ACS Applied Materials and Interfaces

The scientists deposited Sn/Pb intermixed FASn_1–xPb_xI₃ (x = 0.25, 0.5, and 0.75)-based perovskite thin films through inkjet printing. The study focused on finding the ideal composition ratio for a favorable photovoltaic performance. The deposited FASn_1–xPb_xI₃ thin films were subjected to various characterizations followed by their implementation in solar cells. 

Zinc-ion batteries (ZIBs) are emerging as a candidate for use as an efficient and sustainable energy storage solution, offering advantages in terms of cost-effectiveness, safety, and performance. The key to commercializing ZIBs lies in developing cathode materials that offer high specific capacity and prolonged cycle performance. 

In a recent study, researchers from the Indian Institute of Science and University of Melbourne have demonstrated the capability of environmentally friendly, lead-free inorganic perovskites for high-rate rechargeable aqueous zinc-ion batteries with enhanced stability and excellent rate performance.

Researchers from China's Shaanxi Normal University, Zhejiang Normal University, China Institute of Radiation Protection and Chinese Academy of Sciences have developed lead-free photoferroelectric hybrid metal halide perovskite flexible membranes for wearable detectors, that offer excellent X-ray response with high sensitivities, low detection limit and impressive imaging capabilities. 

Demonstration and application potential for lead-free photoferroelectric perovskite membrane (LFPPM). a) Optical images of the LFPPM. b) Schematic diagram of LFPPM wearable X-ray dosimeter. c) Schematic diagram of the working principle of wearable X-ray dosimeter. (Image credit: Nanowerk)

High-sensitivity wearable radiation detectors are important for personnel protection in radiation environments such as defense, nuclear facilities, and medical fields. Traditional detectors using bulk crystals tend to lack flexibility. Hybrid metal halide perovskites have shown promise for next-generation radiation detection as they can efficiently absorb high-energy radiation and convert it into electrical signals. However, there are concerns of lead toxicity. More recent efforts have explored lead-free alternatives, but these have generally suffered from poor charge transport properties, reducing their effectiveness as radiation detectors.

Researchers from India's Chiktara University have reported improved stability and performance of organic-inorganic perovskite solar cells by applying a strategy called bandgap grading.

The method is based on enabling the cell perovskite absorber to collect a wider range of light photons by modifying its thickness and characteristics. The team explains that its recent study demonstrates the effectiveness of both linear and parabolic bandgap grading strategies in optimizing light absorption and boosting performance, showing its potential. 

Lead-halide perovskites hold great promise as the next generation of PVs, but unstable lead exposure through gas, water, and soil accumulation could have detrimental consequences if not properly controlled and recycled as perovskite use expands globally. There are also stability issues limiting operational lifetime for lead-perovskite devices themselves. Researchers have attempted to replace lead with slightly less toxic tin, but thus far tin-based perovskites still suffer from air instability. Without breakthroughs in stability and environmental safety, scaling perovskite solar technology could flood our waste stream with hazardous materials. Now, researchers from CHOSE (Centre for Hybrid and Organic Solar Energy) at the University of Rome Tor Vergata have addressed the concerns regarding toxicity and recyclability associated with the lead contained in perovskite solar cells. 

Image credit: ACS Energy Letters 

The scientists may have found a solution in a new lead-free antimony-based perovskite solar cell design. Their recent research demonstrates a mixed-cation perovskite-inspired material (PIM) that boosted efficiency by 81% compared to conventional cesium-only antimony solar cells, while also exhibiting unmatched stability.

Researchers from Japan's University of Electro-Communication and CAR MATE MFG. CO. have developed a lead-free tin sulfide solar cell that is intended for applications in tandem perovskite-silicon PV devices. 

Using a new passivation technique based on the use of phenylsilane (PhSiH₃) as a reducing agent, the scientists were able to considerably increase the cell's efficiency compared to a reference device with no PhSiH₃ treatment.

Researchers from Southeast University and the University of Liberal Arts Bangladesh have designed and simulated an all-inorganic lead-free tandem photovoltaic cell based on copper, indium, gallium and selenium (CIGS) thin-film technology and perovskite.

The proposed top cell (a) and bottom cell (b), image from Heliyon

The novel device architecture is said to have the potential to reach a power conversion efficiency of 38.39%. “The main objective of this work is to find an efficient combination of non-toxic solar cells with high efficiency so that it saves time and effort before going for fabrication,” the scientists said in their work, noting that the perovskite and materials used for the cell are lead-free.

Researchers from Southeast University in Bangaladesh and U.S-based Rochester Institute of Technology have examined the performance of a lead-free Cs₂TiX₆-based n–i–p type heterostructure perovskite solar cell design, performed using a one-dimensional device simulator, also known as the SCAPS-1D. 

The design makes use of Cs₂TiCl₆ as an n-type front absorber, Cs₂TiI₆ as an I (intrinsic)-layer absorber and Cs₂TiBr₆ as a p-type absorber. NiO (p) and ZnO (n) are utilized as the hole transport material and electron transport material. The fluorine-doped tin oxide (FTO) acts as a front contact, conductive oxide, while Pt (platinum) is used as the back contact. 

Researchers from Zhengzhou University and the Chinese Academy of Sciences (CAS) have devised a novel lead capturing technique for perovskite solar cells: they implanted a multifunctional mesoporous amino-grafted-carbon net into the perovskite solar cells, creating biomimetic cage traps that could effectively mitigate Pb leakage and shield from external invasion under extreme weather conditions. 

The team then explored the synergistic Pb capturing mechanism in terms of chemical chelation and physical adsorption. Additionally, the Pb contamination assessment of end-of-life perovskite solar cells in the real-world ecosystem, including Yellow River water and soil, was proposed by the scientists. 

Researchers from China's Zhejiang University and South China University of Technology have developed transparent glassy composites based on lead-free anti-perovskites in a novel approach that could revolutionize X-ray imaging.

There is a high demand for high-resolution and ultrastable X-ray imaging methods in various fields, like material inspection, medical diagnostics, astronomical discovery, and scientific research. This demand has ignited a vigorous pursuit of innovative X-ray-responsive materials that must possess exceptional qualities such as high X-ray attenuation, efficient scintillation, rapid light decay, and robust durability. Among them, lead-halide-based perovskites have emerged as a compelling contender due to their remarkable luminescence efficiency, superior X-ray attenuation capabilities, and short fluorescence lifetimes. However, their application in the scintillation field is hindered by the toxicity of heavy metal lead (Pb), low photon yield caused by self-absorption effects, and poor X-ray irradiation stability.