Recent Advances in Lead‐Safe Perovskite Solar Cells

Abstract

Perovskite solar cells (PSCs) have made unprecedented progress in improving power conversion efficiency in the past decade, and they are considered as one of the most promising photovoltaic technologies. However, the commercialization of PSCs still faces significant challenges, such as the stability issue and toxicity of lead. Recently, pursuing ways to alleviate the toxicity of lead has emerged as an attractive research direction in the community of PSCs. In this review, the discussion is on the toxicity of lead and the impact of lead leakage from perovskites to the environment, the recent progress made to reduce the leakage of lead is presented with an emphasis on the lead sequestration materials applied in encapsulation layers and functional layers of PSCs, and the recovery of lead from damaged or decommissioned PSC devices is concisely summarized. This review may serve as a guide for researchers interested in promoting PSCs from exploitation to application.

Additive Engineering for Mixed Lead–Tin Narrow-Band-Gap Perovskite Solar Cells: Recent Advances and Perspectives

“…PSCs are regarded as one of the most promising photovoltaic technologies because of the high light absorption coefficients and carrier mobility, long carrier diffusion length, and low manufacturing cost. , Although the PCEs of Pb-based PSCs have reached 25.7% recently, the commercialization is still limited by the toxicity of Pb, inherent wide band gap, and inferior stability . Replacing Pb with Sn at the B site is considered as an effective and simple solution to tackle the above-mentioned problems, enabling sustainable and clean perovskite photovoltaics.…”

“…47,104 Although the PCEs of Pb-based PSCs have reached 25.7% recently, the commercialization is still limited by the toxicity of Pb, inherent wide band gap, and inferior stability. 35 Replacing Pb with Sn at the B site is considered as an effective and simple solution to tackle the above-mentioned problems, enabling sustainable and clean perovskite photovoltaics. In comparison to pure Sn-based perovskites, mixed Pb−Sn perovskites have several distinct advantages: (1) The band gaps can be welladjusted in the range of 1.17−1.55 eV by tailoring the Pb/Sn ratios, exhibiting ideal band gaps close to the S−Q limit, which can function as ideal NBG subcells for all-perovskite TSCs.…”

“…The new third-generation solar cells, such as perovskite solar cells (PSCs), dye-sensitized solar cells, and quantum dot solar cells, have received increasing interests recently as a result of the facile fabrication process, low-cost raw material, and superior theoretical PCEs. − In particular, PSCs with lead (Pb)-based halide perovskites as light absorbers exhibit several unique and excellent optical/electronic properties, including adjustable band gaps, high optical absorption coefficients, high mobility, and long diffusion length of charge carriers, leading to a rapid boosting rate of PCEs of PSCs from 3.8 to 25.7% in the last 14 years. − Therefore, the newly developed PSCs are considered as the most potential replacements to traditional silicon-based solar cells for large-scale and sustainable photovoltaic power generation. , Although the PCEs of Pb-based PSCs have reached 25.7% recently, the large-scale applications of Pb-based organic–inorganic hybrid PSCs still face many crucial challenges. − First, the band gaps of Pb-based organic–inorganic perovskites currently used in high-performance PSCs are generally 1.5–1.6 eV, which are much larger than the theoretical optimal band gap of 1.3–1.4 eV for solar cells calculated according to the Shockley–Queisser (S–Q) theory . Second, the toxicity of Pb is extremely harmful to the environment and humans. − To overcome these problems, numerous researchers are trying to develop new Pb-free or Pb-less halide perovskites using non-toxic metals, including tin (Sn), bismuth (Bi), and germanium (Ge), to achieve sustainable and clean perovskite photovoltaics. − Among various alternatives to Pb 2+ cations, Sn 2+ cations have similar electronic structures to Pb 2+ and comparable ion radii (the ionic radii of Sn 2+ and Pb 2+ are 110 and 119 pm, respectively). − Therefore, partial or complete replacement of Pb 2+ in perovskites by Sn 2+ will not lead to significant lattice distortions in the perovskite structure .…”

Recycling Useful Materials of Perovskite Solar Cells toward Sustainable Development

“…The development of recycling strategies for Pb‐containing chemicals is challenging, which affects the safe and eco‐friendly application of PSCs. [ 155 ]…”

Design potential and future prospects of lead-free halide perovskites in photovoltaic devices

“…33 In addition, the problem of lead ion leakage from the encapsulated devices still persists, leading to the entering of the lead ions into the environment through moisture and rain. 34,35 Thus, it is of great interest and necessity to search for non-lead-based ions to use in perovskite materials to build environmentallyfriendly and stable materials.…”