Potential lead toxicity and leakage issues on lead halide perovskite photovoltaics

Ren, Meng; Qian, Xufang; Chen, Yuetian; Wang, Tianfu; Zhao, Yixin

doi:10.1016/j.jhazmat.2021.127848

Cited by 185 publications

(123 citation statements)

References 92 publications

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“…Despite having notable efficiency and exceptional optoelectronic characteristics, lead-halide perovskites are still a long way from the commercialization or real-world acceptance because of important concerns such as the toxicity of lead (Pb) and the poor stability of lead-based perovskites in the presence of heat, oxygen, moisture, electric field, and light. − As an alternative to lead, bismuth-based perovskites have emerged, where both of the above-said problems of lead perovskites can be addressed simultaneously. − Consequently, metal-halide lead-free halide double perovskites with A 2 B(I)B(III)X 6 composition are recently surging as promising alternatives for Pb-based halide-perovskites. − Of these double perovskites, Cs 2 AgBiBr 6 has gained considerable attention in both photovoltaics and detection applications, with high stability and low toxicity. − Indeed, to date, Cs 2 AgBiBr 6 -based solar cells exhibited a power conversion efficiency of more than 4%, and Cs 2 AgBiBr 6 single crystals-based X-ray detectors demonstrate high sensitivity and low detection of the limit of 59.7 nGy/s …”

Section: Introductionmentioning

confidence: 99%

Dielectric Relaxation and Polaron Hopping in Cs₂AgBiBr₆ Halide Double Perovskites

et al. 2022

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The lead-free Cs2AgBiBr6 double perovskites have recently emerged as promising candidates for optoelectronic applications due to their less toxicity and high stability. Although the photophysical study of Cs2AgBiBr6 has been extensively explored, the same for dielectric relaxation and carrier conduction remains elusive. Here, we uncover the dielectric relaxation and charge conduction mechanism in the Cs2AgBiBr6 single crystals using temperature-dependent electrochemical impedance spectroscopy in correlation with modulus spectroscopy. We found that the ionic displacement and space charge polarization are mainly responsible for the dielectric response. A sharp transition frequency as ∼191 Hz for 0 °C to ∼492 Hz for 90 °C was observed in the dielectric constant (ε′) versus temperature study, where dε′/dT exhibits a positive and negative coefficient below and above the transition frequency, respectively. Stevels model analysis suggests that the contribution of traps reduces with the increase in temperature and therefore conduction enhances. This model also confirms the polarons as the main conduction carriers in the Cs2AgBiBr6 semiconductor. The polaron hopping and binding energy were estimated as W H = 0.17 eV and E P = 0.34 eV, respectively. The binding energy of the polaron is larger than the room-temperature thermal energy, indicating the polaron hopping instead of free charge carrier transport as the dominant conduction mechanism. Furthermore, the imaginary part of -Z″ and M″ demonstrates the temperature-activated polaron relaxation from non-Debye type to Debye type process in Cs2AgBiBr6 crystals. Our study provides fundamental insights into the dielectric relaxation behavior needed for developing efficient dielectric switches and unveils the details of the carrier conduction mechanism in lead-free double perovskites.

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Section: Introductionmentioning

confidence: 99%

Dielectric Relaxation and Polaron Hopping in Cs₂AgBiBr₆ Halide Double Perovskites

et al. 2022

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“…X-ray detection and imaging have been used extensively in various applications such as medical diagnostics, nondestructive inspection, security screening, and scientific research. − Although conventional semiconductors, for example, cadmium telluride (CdTe), amorphous selenium (α-Se), and silicon (Si), have been applied extensively as X-ray detectors, they suffer from small Z (atomic number), insufficient mobility lifetime (μτ), and high processing cost. − To satisfy the requirement of high sensitivity for direct X-ray detectors, it is critical to prepare superior semiconductor materials at a reasonable cost. Recently, lead-halide perovskite single crystals (SCs) with large atomic numbers and high μτ products have been considered as a strong candidate for X-ray detectors with high performance at a lower cost. − Although lead halide perovskites have made significant progress, − their practical applicability is still limited due to the usage of potentially toxic lead and inherent ion migration properties leading to baseline drift and deteriorated image resolution. ,, Metallic lead (Pb) can cause serious neurological and nephrological problems. , Therefore, it is imperative to find Pb-free solution-processed perovskite SCs to meet the demands of high-performance X-ray detectors with good imaging capability.…”

Section: Introductionmentioning

confidence: 99%

Self-Powered X-ray Detection and Imaging using Cs₂AgBiCl₆ Lead-Free Double Perovskite Single Crystal

Tailor

Ghosh

Afroz

et al. 2022

ACS Appl. Electron. Mater.

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Despite the high performance of lead-halide perovskite-based X-ray detectors, the toxicity and instability of lead require the development of lead-free perovskites for X-ray detection applications. Here, we demonstrate lead-free and environmentally friendly, all-inorganic millimeter-sized Cs2AgBiCl6 double perovskite single crystal (SC) for X-ray detection and imaging. The high dark resistivity (3.1 × 1010 Ω cm), high carrier mobility-lifetime product (5.36 × 10–4 cm2 V–1), and lower trap density (1.18 × 109 cm–3) in these double perovskite SCs render them a potential material for X-ray detection. The fabricated vertical structured X-ray detector exhibits a sensitivity of 325.78 μC Gy air–1 cm–2 and a limit of detection of 241 nGy s–1. Additionally, the Cs2AgBiCl6 SCs exhibit self-powered X-ray detection at zero bias with a sensitivity of 7 μC Gy air–1 cm–2. Moreover, the fabricated perovskite X-ray detector exhibits a stable and robust performance under continuous X-ray irradiation and long-term ambient storage. Further, we demonstrated the imaging capability of the Cs2AgBiCl6 X-ray detector using a metal test object and obtained a distortion-free image. Our findings demonstrate that the Cs2AgBiCl6 single crystal-based X-ray detectors have great potential as practical X-ray detectors and imaging for medical radiography.

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“…[59] Regarding the characteristics of Pb in water, Pb can be easily migrated via rain, and then constantly accumulated in water. [60][61][62] Babayigit et al simulated the acute toxicity test of perovskites in water by adding PbI 2 to the growth environment of zebrafish embryos. [63] They found that low concentrations of PbI 2 distorted most zebrafish embryos, and 1.60 mm PbI 2 was extremely lethal to zebrafish embryos.…”

Section: Pb Contamination In the Ecosystemmentioning

confidence: 99%

Sustainable Pb Management in Perovskite Solar Cells toward Eco‐Friendly Development

Luo

et al. 2022

Advanced Energy Materials

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of human society. Clean and green solar energy could be converted into electric energy through photovoltaic technologies. This can provide a green and sustainable way for energy utilization. [1][2][3] Inorganicorganic hybrid perovskite solar cells (PSCs) are considered to be one of the most promising photovoltaic applications, [4][5][6][7][8][9][10][11] owing to the favorable properties of perovskite materials, such as tunable bandgap, high absorption coefficient, large bipolar mobility, long carrier diffusion length, small exciton binding energy and high defect tolerance. [12][13][14][15][16][17][18] The best power conversion efficiency (PCE) of PSCs has reached 25.7% based on Pb-based perovskites, which has exceeded that of monocrystalline silicon solar cells and exhibited huge a market prospect. [19] However, these perovskite films are prone to be decomposed into the toxic heavy-metal compounds of PbI 2 , Pb, or PbO, etc. because of the uncontrollable environmental condition, including high temperature, high humidity, and strong sunlight. [20,21] The toxicity of Pb leaking from perovskite film has become one of the main obstacles toward commercialization. [22] There have been extensive endeavors to replace Pb with Sn to make the perovskite active layer less toxic, however, Sn-based PSCs demonstrate inferior efficiency and stability compared with their Pb-based counterparts. Thus, the Pb-based perovskites are still indispensable for guaranteeing excellent photoelectric properties and would be the main force of future large-scale applications.The photovoltaic market has been growing rapidly for alleviating energy scarcity and mitigating climate change. The cumulative solar capacity in 2020 reaches ≈773.2 GW around the world. [23] If 20% of this solar capacity is occupied by perovskite solar panels with 500 nm Pb-based perovskite film and ≈20% PCE, 541.24 tons of Pb would be consumed considering ≈0.70 g m −2 of Pb content. [24,25] The widespread deployment of PSCs would provoke a terrible environmental pollution without proper Pb management. World Health Organization (WHO) and many countries have reached a broad consensus on the restriction of the Pb pollution and established strict environmental standards on the Pb usage. Besides, international organizations such as the European Union have also formulated relevant regulations for the management and regulation of waste electrical and electronic equipment, requiring producers to take responsibility for collecting and recycling apparatus waste. [26] Therefore, sustainable Pb management is an essential prerequisite for the commercialization of PSCs. Pb-based perovskite solar cells (PSCs) as one of the most promising photovoltaic technologies for commercialization have attracted tremendous attention in recent years. However, the toxicity and leakage of heavy metal Pb from perovskite film have become critical obstacles for eco-friendly development. Extreme weather conditions such as heavy rain, high temperature, or strong sunlight may accelerate the undesired decomp...

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Potential lead toxicity and leakage issues on lead halide perovskite photovoltaics

Cited by 185 publications

References 92 publications

Dielectric Relaxation and Polaron Hopping in Cs₂AgBiBr₆ Halide Double Perovskites

Dielectric Relaxation and Polaron Hopping in Cs₂AgBiBr₆ Halide Double Perovskites

Self-Powered X-ray Detection and Imaging using Cs₂AgBiCl₆ Lead-Free Double Perovskite Single Crystal

Sustainable Pb Management in Perovskite Solar Cells toward Eco‐Friendly Development

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Potential lead toxicity and leakage issues on lead halide perovskite photovoltaics

Cited by 185 publications

References 92 publications

Dielectric Relaxation and Polaron Hopping in Cs2AgBiBr6 Halide Double Perovskites

Dielectric Relaxation and Polaron Hopping in Cs2AgBiBr6 Halide Double Perovskites

Self-Powered X-ray Detection and Imaging using Cs2AgBiCl6 Lead-Free Double Perovskite Single Crystal

Sustainable Pb Management in Perovskite Solar Cells toward Eco‐Friendly Development

Contact Info

Product

Resources

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Dielectric Relaxation and Polaron Hopping in Cs₂AgBiBr₆ Halide Double Perovskites

Dielectric Relaxation and Polaron Hopping in Cs₂AgBiBr₆ Halide Double Perovskites

Self-Powered X-ray Detection and Imaging using Cs₂AgBiCl₆ Lead-Free Double Perovskite Single Crystal