Perovskite materials have become one of the most intensively studied families of functional semiconductors in modern materials science, and a new comprehensive review published in the journal Discover Nano on 23 October 2026 sets out both their remarkable promise and their uncomfortable environmental baggage. Written by Mohammad Khalid, Tenzin Thinley, Harini Revanna, Ahmed I. Foudah, Mohammed H. Alqarni and Harikaranahalli Puttaiah Shivaraju, the review compiles recent research on the fundamentals, synthesis, characterization and applications of perovskites, with a particular focus on what happens when these materials meet the environment.
The story begins with a mineral. Calcium titanate, CaTiO3, was the first material to be called a perovskite, discovered in 1839 by the mineralogist Gustav Rose and named in honour of the Russian mineralogist Lev Perovski. Materials sharing its crystal chemistry are now grouped under the same banner, defined by the general formula ABX3, in which A and B are cations, with A generally the larger atom, and X is an anion, predominantly oxygen but also halides. The idealized cubic structure places a six-fold coordinated B cation inside an octahedron of anions, with the A cation at the centre in twelve-fold cuboctahedral coordination. In practice, that perfect symmetry is rarely achieved. Crystal defects such as oxygen vacancies drive distortions into orthorhombic and tetragonal phases, and this off-centring of the B cation is responsible for the pyroelectric and other unique electromagnetic behaviours that make perovskites so versatile. Doping subdivides the family further, and halide perovskites, especially organic-inorganic metal halides, have become stars of the photovoltaic field.
Understanding these materials depends on an arsenal of characterization techniques. Scanning electron microscopy reveals structural morphology, field-emission SEM offers higher resolution, and transmission electron microscopy probes crystal structure and lattice parameters; one TEM study reported hollow rods of strontium titanate with enhanced surface for photocatalysis. X-ray diffraction establishes crystallinity and phase purity and can track structural degradation over a material’s lifetime, while Fourier-transform infrared spectroscopy probes interactions with water and impurities, energy dispersive spectroscopy identifies elemental composition, and BET, BJH, Raman and UV-vis measurements deliver surface area, pore size distribution, turnover frequency and bandgap. In one reported example, caesium lead halide nanocrystals synthesized in a single pot were confirmed by SEM, TEM and EDS to be below 20 nanometres, free of impurities, with sharp photoluminescence peaks indicating a narrow emission range. These optical and electronic traits, including high absorption coefficients, long charge-carrier diffusion lengths, tuneable bandgaps, low exciton binding energies and relatively high charge carrier mobilities, underpin the materials’ performance in photocatalysis and optoelectronics.
Synthesis routes shape everything that follows. The ceramic method, one of the oldest, mills precursors into fine powder and calcines them repeatedly above 1000 degrees Celsius, yielding phase-pure crystalline bulk material cheaply but with coarse particles, defects and a high carbon footprint. Chemical co-precipitation offers a more economical one-pot alternative with structural and morphological control; barium titanate prepared by an oxalate co-precipitation route succeeded at 700 degrees Celsius, a 200-degree reduction from the ceramic route. Sol-gel synthesis, the most widely used technique, crosslinks precursor molecules through an organic chelating agent and produces porous, high-surface-area material suited to catalysis and electrodes, though it may not suit applications needing isolated nanoparticles. Hydrothermal processing, heat treatment above 100 degrees Celsius and above 1 bar in a sealed vessel, allows fine control of size and shape through additives, temperature, pressure and duration, with solvothermal variants using organic solvents when salts dissolve poorly in water. Electrospinning produces one- and two-dimensional nanofibres whose fineness scales with applied voltage, but it suffers from low yield and high energy consumption.
On the application side, the review catalogues striking laboratory results. Strontium titanate produced hydrothermally degraded more than 97 percent of methylene blue within 90 minutes under ultraviolet light, while a tungstate layered double hydroxide made solvothermally demineralized 95 percent of methyl orange under visible light. Lead-free double halide perovskite Cs2AgBiBr6 achieved more than 98 percent demineralization of dye under visible illumination. Against contaminants of emerging concern, a sodium niobate-doped graphitic carbon nitride perovskite heterojunction degraded 69 percent of the antibiotic ofloxacin within one hour under UV irradiation, and a graphitic carbon nitride-doped lanthanum-copper-cobalt oxide destroyed 98 percent of bisphenol A within two minutes under microwave-induced catalysis. A metal-organic-framework-derived lanthanum cobalt oxide reached 99.8 percent degradation of the herbicide precursor 2,4-dichlorophenol in 25 minutes through peroxy-monosulphate activation. In water treatment itself, a sol-gel lanthanum ferrite nanostructure removed up to 86.34 percent of cadmium, a biosynthesized bismuth ferrite perovskite removed six heavy metals including nickel, zinc, cobalt, copper, lead and mercury, and lanthanum aluminate adsorbed fluoride with a Langmuir maximum of 40.8 milligrams per gram alongside biocidal activity.
Energy applications feature prominently too. Photocatalytic and photo-electrocatalytic water splitting, which requires a minimum potential difference of 1.23 volts, has been demonstrated across a range of perovskites: a lanthanum and nitrogen co-doped strontium titanate nitride generated hydrogen at 16 micromoles per hour per gram and oxygen at 13, lanthanum tantalate nanosheets reached quantum efficiencies of 1.29 percent for hydrogen and 3.27 percent for oxygen generation, and a reduced graphene oxide and nickel oxide doped lanthanum ferrite made by sol-gel produced 930 micromoles of hydrogen per gram per hour over four hours. For carbon dioxide reduction, caesium bismuth iodide nanocrystals yielded 14.9 micromoles per hour per gram of methane and 77.6 of carbon monoxide, outperforming conventional TiO2, and a metal-doped halide perovskite reached 1724 micromoles per hour per gram, 26 times its undoped counterpart. In photovoltaics, solution-based planar CH3NH3PbI3 cells have achieved 15.4 percent solar conversion, inorganic lead halide cells reached 17 percent with function over 1500 hours, and silicon-perovskite tandem cells attained 35 percent power conversion, surpassing the theoretical Shockley-Queisser limit for a single junction. Ceramic perovskites are also being explored for energy storage, with a bismuth sodium titanate material showing 94 percent energy storage efficiency and a density recovery of 5.63 joules per cubic centimetre at 535 kilovolts per centimetre.
Yet the review is blunt about the hazards. Many commercially attractive perovskites contain lead, a well-known toxic heavy metal. Lead leakage from degraded perovskite solar cells poses contamination risks to soil and water with potential long-term ecological consequences, and without effective encapsulation and recycling strategies, lead ions can leach and become a pollution source. Lead halide perovskites are unstable under ambient conditions, and moisture triggers hydration and hydrolysis; one study of moisture influence reported 60 percent lead leaching within the first 120 seconds of aqueous exposure. Synthesis carries its own footprint: high-temperature sintering of oxide perovskites leaves a substantial carbon footprint, and a comparison of green synthesis against ultrasonicated sol-gel for lanthanum ferrate found the green route had a 50 percent higher carbon footprint, with a global warming potential of 33.52 kilograms of CO2 equivalent. Even lead zirconate titanate, a commercial piezoelectric staple that is at least 60 percent lead by mass, requires excess lead oxide during synthesis to compensate for volatilisation, creating severe environmental and health hazards if mishandled.
Perhaps most sobering, the alternatives are not automatically safe. Experimental evidence cited in the review demonstrates that perovskite nanocrystals induce cytotoxicity, oxidative stress and DNA damage in human cell lines, while aquatic organisms exposed to these materials showed impaired growth and survival. The study also warns that substitutes safer in bulk form may not be safe at the nanoscale: lead-free bismuth perovskite showed a toxicity profile similar to lead in zebrafish and human cells. Doped lead-free halides bring their own concerns, since chromium-doped Cs2AgBiCl6, emitting at 825 nanometres with 26 percent photoluminescence quantum yield, and bismuth-doped Cs3Mo2Cl9, emitting at 447 nanometres with 8 percent quantum yield, still contain heavy metal dopants that can leach into the environment. The review suggests artificial intelligence could accelerate the search for safer, efficient lead-free compositions, enhance mechanistic understanding and generate life cycle assessments.
The authors close with a clear agenda. Future perovskite research should prioritize stable, lead-free compositions with high conversion efficiency, water-stable formulations, surface passivation, protective coatings and immobilized photocatalysts that minimize secondary contamination. Catalyst performance, they argue, must be validated in real wastewater with long-term cycling, mineralization and toxicity assessment rather than pollutant removal in model solutions alone. Regulatory frameworks and international standards for toxicity management and life-cycle assessment should be established as more perovskite materials approach commercialisation, and circular economy approaches could reduce environmental impact. Perovskites may indeed help power a sustainable future, but only if their own toxic trail is confronted first.
Subject of Research: Environmental implications, synthesis, characterization and applications of perovskite materials
Article Title: Environmental implications of perovskite materials with a comprehensive review on fundamentals, synthesis, characterization, and applications
Article References: Khalid, M., Thinley, T., Revanna, H., Foudah, A. I., Alqarni, M. H., & Shivaraju, H. P. (2026). Environmental implications of perovskite materials with a comprehensive review on fundamentals, synthesis, characterization, and applications. Discover Nano, 21(1), Article 555. https://doi.org/10.1186/s11671-026-04968-x
Image Credits: AI Generated
DOI: 10.1186/s11671-026-04968-x
Keywords: perovskites, photocatalysis, water treatment, lead toxicity, solar cells, CO2 reduction, water splitting, synthesis methods, dye degradation, energy storage, sustainability, nanomaterials
News Source: Faith Mcneil. (October 29, 2026). Perovskite Materials Promise Green Gains but Carry Lead and Toxicity Risks. Scienmag.
