A short overview of the lead iodide residue impact and regulation strategies in perovskite solar cells

Lead iodide(PbI2) is a vital raw material for preparing perovskite solar cells(PSCs),and it not only takes part in forming the light absorption layer but also remains in the grain boundary as a passivator.In other words,the PbI2 content in the precursor and as formed film will affect the efficiency and stability of the PSCs.With moderate residual PbI2,it passivates the bulk/surface defects of perovskite,reduces the interfacial recombination,promotes the perovskite stability,minimizes the device hysteresis,and so on.Deficient PbI2 residue will reduce the interfacial passivation effect and device performance.In addition to facilitating the non-radiative recombination,over PbI2 residue can also lead to electronic insulation in the grain boundary and deteriorate the device performance.However,the impact and regulation of PbI2 residue on the device performance and stability is still not fully understood.Herein,a comprehensive and detailed review is presented by discussing the PbI2 residue impact and its regulation strategies(i.e., elimination,facilitation and conversion of the residue PbI2) to manipulate the PbI2 content,distribution and forms.Finally,we also show future outlooks in this field,with an aim to help further the progression of high-efficiency and stable PSCs.

Lead Iodide Crystals as Input Material for Radiation Detectors

Lead iodide is an important inorganic solid for fundamental research and possible technological applications and is considered to be a potential room temperature nuclear radiation detector. In lead iodide the phenomenon of polytypism is posing an interesting problem of phase transformations amongst its various polytypic modifications. The transformations have also been observed even when the crystals are stored for few months. It causes deterioration in functioning of PbI2 devices. Taking into account the known structures of PbI2 and the data available on the mode of growth and storage of crystals, it has been concluded that purified melt grown crystals of PbI2 are the best suited for nuclear radiation detectors.

Stabilization of formamidinium lead iodide perovskite precursor solution for blade-coating efficient carbon electrode perovskite solar cells

Formamidinium lead triiodide(FAPbI_(3))is a research hotspot in perovskite photovoltaics due to its broad light absorption and proper thermal stability.However,quite a few researches focused on the stability of the FAPbI_(3) perovskite precursor solutions.Besides,the most efficient FAPbI_(3) layers are prepared by the spin-coating method,which is limited to the size of the device.Herein,the stability of FAPbI_(3) perovskite solution with methylammonium chloride(MACl)or cesium chloride(CsCl)additive is studied for preparing perovskite film through an upscalable blade-coating method.Each additive works well for achieving a high-quality FAPbI_(3) film,resulting in efficient carbon electrode perovskite solar cells(pero-SCs)in the ambient condition.However,the perovskite solution with MACl additive shows poor aging stability that noα-FAPbI_(3) phase is observed when the solution is aged over one week.While the perovskite solution with CsCl additive shows promising aging stability that it still forms high-quality pureα-FAPbI_(3) perovskite film even the solution is aged over one month.During the solution aging process,the MACl could be decomposed into methylamine which will form some unfavored intermediated phase inducingδ-phase FAPbI_(3).Whereas,replacing MACl with CsCl could effectively solve this issue.Our founding shows that there is a great need to develop a non-MACl FAPbI_(3) perovskite precursor solution for cost-effective preparation of pero-SCs.

Bioprocess-inspired Fabrication of Lead Iodide Coexisting with Crystalline Nanosheet and Amorphous Nanorod for Perovskite Solar Cells

A recombinant protein ChiSifiCa,which was originally designed for regulation of calcium carbonate,was utilized to direct the mineralization of PbI_(2).By the regulation of ChiSifiCa protein,PbI_(2)nanoparticles composed of crystalline nanoflakes and amorphous nanorods were fabricated under environmental benign conditions.Synthetic PbI_(2)was successfully applied for preparation of perovskite precursors to fabricate solar cells.This regulation of ChiSifiCa on PbI_(2)improves the power conversion efficiency of corresponding perovskite solar cells to 16%.The present study may open a new avenue in the design and synthesis of materials with novel structures and functions.

Adsorption of Lead(II),Copper(II) on tourmaline from Altai mine in China's Sinkiang

Tourmaline from Altai mine in China＇s Sinkiang was used to remove lead （II）, copper （II） from aqueous solution. The results demonstrate that tourmaline contains Na（Mg,V）3AI6（BO3）3Si6Ols （OH）4, NaFe3AI6（BO3）3Si6Ols（OH）4. The data show that Tourmaline from Altai mine in China＇s Sinkiang can be used natural adsorbent for lead （II）, copper （II）.It is observed that the adsorption data fitted to the Langmuir isotherm. Furthermore, both Pb （II） and Cu （II） absorbed by tourmaline and tourmaline were characterized by X-ray diffraction, Laser Raman Spectrum, Fourier transform infrared spectroscopy, X-ray energy dispersive spectrometer, Transmission electron microscopy and Zeta potential.

Evaluation of Biosorptive Capacity of Banana (<i>Musa paradisiaca</i>) Stalk for Lead(II) Removal from Aqueous Solution

Raw Banana Stalk (RBS), Acid Activated Banana Stalk (AABS) and Base Activated Banana Stalk (BABS) prepared from banana stalk were used as biosorbents to remove Lead(II) from aqueous solution. The biosorbents were characterised using proximate analysis and Fourier Transform Infrared (FTIR) spectroscopy. Pb(II) of 1000 mg/L concentration was prepared from Pb(NO3)2 salt and other concentrations were obtained from this stock through serial dilution. Effects of adsorbent dose, temperature, initial metal concentration, contact time and pH on the percentage Pb(II) removal were evaluated. The Pb(II) concentrations in the solutions were analysed using Atomic Absorption Spectrophotometer. Kinetic, isotherm and thermodynamic parameters were determined. FTIR spectroscopy showed that RBS, AABS and BABS are rich in carboxyl, hydroxyl and phenolic functional groups. At an equilibrium time of 180 minutes, the percentage Pb(II) removal was 63.97%, 96.13% and 66.90% for RBS, AABS and BABS, respectively. Pseudo-second order kinetics best described the process with R2 (0.95, 0.98, 0.97) for RBS, AABS and BABS, respectively. Langmuir isotherm (AABS) has the maximum adsorption capacity (qmax) of 13.53 mg/g and R2 (0.99). Thermodynamic parameters obtained were △G0 (?18.75 kJ/mol), △H0 (12.63 kJ/mol), △S0 (0.05 kJ/mol·K) and Ea (4.37 kJ/mol). Banana stalk has viable characteristics for preparing biosorbents. Acid activated banana biosorbent is more efficient for removal of lead ions from its aqueous solution.

Efficiency enhancement of Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) perovskite solar cell by surface passivation using iso-butyl ammonium iodide

Efficiency enhancement of Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) solar cell devices was performed by using iso-butyl ammonium iodide(IBA)passivated on Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) films.The n-i-p structure of perovskite solar cell devices was fabricated with the structure of FTO/SnO_(2)/Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3)(FTO,i.e.,fluorine doped tin oxide)and IBA/Spiro-OMeTAD/Ag.The effect of different weights of IBA passivated on Cs-doped perovskite solar cells(PSCs)was systematically investigated and compared with non-passivated devices.It was found that the 5-mg IBA-passivated devices exhibited a high power conversion efficiency(PCE)of 15.49%higher than 12.64%of non-IBA-passivated devices.The improvement of photovoltaic parameters of the 5-mg IBA-passivated device can be clearly observed compared to the Cs-doped device.The better performance of the IBA-passivated device can be confirmed by the reduction of PbI_(2) phase in the crystal structure,lower charge recombination rate,lower charge transfer resistance,and improved contact angle of perovskite films.Therefore,IBA passivation on Cs_(0.1)(CH_(3)NH)_(0.9)PbI_(3) is a promising technique to improve the efficiency of Cs-doped perovskite solar cells.

Bioremediation of Lead(II) from Polluted Wastewaters Employing Sulphuric Acid Treated Maize Tassel Biomass

The ability to modify a waste by-product precursor, maize tassel biomass using sulfuric acid as the activating agent with specific focus on Lead(II) ion from water has been proposed. The treating of maize tassel using sulphuric acid is believed to enhance sorption capacity of Lead(II) ions. For this, batch adsorption mode was adopted for which the effects of initial pH, adsorbent dosage, contact time and initial concentration were investigated. Consequently, it was found that the adsorbent capacity depends on pH;since it increases up to 4.5 and then decreases. The highest percentage of Lead(II) ion removal was achieved in the adsorbent dosage of 1.2 g and at an initial concentration of 10 mg/L metal ion. In an attempt to determine the capacity and rate of Lead(II) removal, isotherm and kinetic data were modeled using appropriate equations. To this end, the adsorption data fitted best into the Langmuir model with an R2 (0.9997) while kinetically the Lead(II) adsorption followed the pseudo-second-order model. Furthermore, as a way to address issues related to sustainability, maize tassel is recommended since the process is considered to be a dual solution for environmental cleaning. From one side, it represents a better way to dispose the maize tassel which has no use after fertilization and on the other hand it is an economic source of carbonaceous materials.

Determination of Lead(II) in Liver Corpse of a Slaughtered Cattle with Preconcentration on a Chelating Sorbent

The copolymer of the maleic anhydride-styrene is modified at the presence of 4-amino-2-thiouracil and formaldehyde and the new polymeric sorbate with spatial structure is received. The received sorbate is identified by the IR-spectroscopy method. The complete static sorption capacitance was studied (CSSC+K= 7.8 mmol/g) and the ionization constants of ionic groups in a sorbate link was defined by electrometric method. Ionization constants were determined by potentiometric titration of the sorbent (). Sorption and desorption of the received sorbent with a lead ion (II) are investigated and optimum concentration conditions are defined: рНopt. = 5, ionic force μ = 0.8 pier/l, full sorption balance 4 hours, optimum eluent 5 ml of 0.5 M HCl.

甲脒/铯基卤化物钙钛矿光伏材料稳定性研究进展

低成本、高效率和长寿命是光伏材料商业化应用必须满足的黄金三角规则。目前,钙钛矿光伏材料在低成本和高效率方面已取得显著进展,但其稳定性仍面临挑战。论文总结了近年来甲脒/铯基卤化物钙钛矿太阳能电池材料稳定性策略的研究进展,包括组分、表面、应力和降维工程四种稳定策略;并进一步总结了甲脒/铯基卤化物钙钛矿太阳能电池材料动力学稳定性的研究工作,该研究将为卤化物钙钛矿太阳能电池材料的稳定策略提供参考。

水蒸气对碘化铅薄膜作用的实验研究

PSC(钙钛矿太阳能电池)被认为是具有潜力的第三代光伏电池,并具备取代硅电池的可能。然而,钙钛矿薄膜制备时难以控制的结晶过程阻碍着它的大规模生产和商业化进程。因此,提出两步法分步沉积碘化铅和甲基碘化铵薄膜,该方法的成膜质量很大程度上取决于第一步沉积的碘化铅层薄膜形貌。为了研究高质量的碘化铅薄膜制备方法,观察高湿度环境下碘化铅薄膜的形貌变化,对比实验前后的碘化铅薄膜的晶体质量,发现水蒸气对碘化铅薄膜形貌具有调控作用。实验结果表明,水蒸气与碘化铅晶体之间存在某种化学作用,从而导致碘化铅的重结晶。在高湿度环境下,合适的作用时间可以改善碘化铅薄膜,为提升钙钛矿薄膜的质量提供思路。

ERP/MRP-II系统动态提前期的研究

在ERP/MRP -II系统中 ,提前期是一个与交货期、库存计划、能力平衡计划等等参数和过程有着密切关系的变量。可以说 ,提前期在ERP/MRP -II系统中具有核心地位。因此提前期的确定也就显得非常重要。从决定提前期的相关因素入手 ,利用神经网络模型 。

基于神经网络动态确定ERP/MRP-II系统提前期的研究

在ERP MRP -II系统中 ,提前期是一个与开发期、交货期、库存计划、能力平衡计划等参数和过程有着密切关系的变量。可以说 ,提前期在ERP MRP -II系统中具有核心地位。因此提前期的确定也就显得非常重要。本文试图从决定提前期的相关因素入手 ,利用神经网络模型 ,确定出能够根据生产条件、环境而改变的动态提前期。

离子交换法测定碘化铅溶度积常数的实验改进

本文针对基于离子交换方法测定碘化铅溶度积常数实验时滴定终点的判定存在的问题进行了创新性改进,采用电子pH计替代传统的溴化百里酚蓝指示剂进行实验。经过对比实验研究表明:改进后的实验计算结果更精确,实验效率更高,实验稳定性得到了明显提升,有利于激发学生的科学创新精神,培养学生独立科研的动手能力,更适合作为典型本科无机化学实验室内的长期教学.

Hydrothermal Synthesis and Crystal Structure of a Lead(Ⅱ) Polymer with a Two-dimensional Network Structure:[Pb_2(PDB)_2(phen)]_n·nH_2O

A new metal-organic complex [Pb2（PDB）2（phen）]n·nH2O （H2PDB=pyridine-3,4-dicarboxylic acid,phen=1,10-phenanthroline） 1 has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,TG and single-crystal X-ray diffraction.The compound crystallizes in triclinic,space group P1 with a=7.2472（5）,b=10.6966（8）,c=16.2376（12）,α=98.2960（10）,β=91.6430（10）,γ=97.4810（10）o,V=1233.53（16）3,C26H16O9N4Pb2,Mr=942.81,Dc=2.538 g/cm3,μ（MoKα）=13.697 mm-1,F（000）=872,Z=2,the final R=0.0247 and wR=0.0654 for 3886 observed reflections （I 〉 2σ（I））.In the crystal structure,the Pb（1） atom is six-coordinated with four carboxylate oxygen atoms from three different PDB ligands and two nitrogen atoms from phen ligand,showing a distorted octahedral geometry;the Pb（2） atom is four-coordinated with four carboxylate oxygen atoms from four different PDB ligands,showing a distorted tetrahedral geometry.It exhibits a three-dimensional supramolecular network structure formed by hydrogen bonds and π-π interactions.

A Novel Two-dimensional Lead(Ⅱ) Coordination Polymer Based on Dinuclear Lead(Ⅱ) Unit Containing(5-Chloro-quinolin-8-yloxy) Acetate

A novel two-dimensional lead（II） coordination polymer 1, [C11H7Cl2NO3Pb]n, has been prepared by solvothermal reaction of new bridging ligand（5-chloro-quinolin-8-yloxy）acetic acid（HL） with PbCl2, and its structure was characterized by IR, elemental analysis, TG-DTA and single-crystal X-ray diffraction analysis. The crystal is of monoclinic system, space group P21/c with a = 16.7603（7）, b = 8.6907（4）, c = 8.4745（3）A, β = 101.1110（11）°, C11H7Cl2NO3 Pb, Mr = 479.27, V = 1211.25（9）A3, Z = 4, Dc = 2.628 g/cm^3, F（000） = 880, μ = 14.367 mm^-1, R = 0.0173 and wR = 0.0508. The asymmetric unit contains one lead（II） cation, one（5-chloro-quinolin-8-yloxy）acetate（L） ligand and a chloride ion. The PbII center is hepta-coordinated in a distorted pentagonal bipyramidal geometry. The coordination sphere of the Pb atom is completed by two oxygen atoms and one nitrogen atom of the same L ligand, two bridging chloride ions and two bridging oxygen atoms of two adjacent L ligands. Two PbII centers are linked by the two L ligands to form a C2-symmetric dimer unit with a planar [Pb2O2] ring. Each dimer unit acts as a secondary building unit（SBU） and links adjacent four dimer units by the chloride atoms and oxygen atoms of carboxylate groups of L, forming a two-dimensional array. Such two-dimensional layers are packed through intermolecular C–H…Cl hydrogen bonds into a three-dimensional supramolecular structure. When the dimer unit is viewed as a 4-connected node, 1 is simplified as a 4-nodal 2-D network with square lattices of the diagonal lengths to be 6.079（1）A. The fluorescence emission peak of complex 1 appears near 407 nm.

Electrochemical behavior and electrolytic preparation of lead in eutectic NaCl−KCl melts

A novel molten salt extraction process consisting of chlorination roasting and molten salt electrolysis was proposed to develop a more efficient and environmental friendly technology for recovering lead from spent lead acid batteries(LABs).The feasibility of this process was firstly assessed based on thermodynamics fundamentals.The electrochemical behavior of Pb(II)on a tungsten electrode in the eutectic NaCl−KCl melts at 700℃ was then investigated in detail by transient electrochemical techniques.The results indicated that the reduction reaction of Pb(II)in NaCl−KCl melts was a one-step process exchanging two electrons,and it was determined to be a quasi-reversible diffusion-controlled process.Finally,potentiostatic electrolysis was carried out at−0.6 V(vs Ag/AgCl)in the NaCl−KCl−PbCl2 melts,and the obtained cathodic product was identified as pure Pb by X-ray diffraction analysis.This investigation demonstrated that it is practically feasible to produce pure Pb metal by electrochemical reduction of PbCl2 in eutectic NaCl−KCl melts,and has provided important fundamental for the further study on lead recovery from spent LABs via molten salt extraction process.

Hydrothermal Synthesis,Structure and Photo-luminescence of a 2D Lead（Ⅱ） Coordination Polymer with （4,6^3）Topology Based on Pb and 1,2,3,4-Butanetetracarboxylate Nodes

A lead（II） coordination polymer,{[Pb2（butca）（H2O）2]（H2O）2}n （1）,has been synthe-sized by the hydrothermal reaction of Pb（OH）2 and 1,2,3,4-butanetetracarboxylic acid （H4butca） at 160 °C.Single-crystal X-ray analyses reveal that it crystallizes in monoclinic,space group P21/c with a=7.616（5）,b=7.584（4）,c=12.314（7）,β=105.595（12）o,V=685.0（7）3,Z=4,C8H14O12Pb2,Mr=716.57,Dc=3.474 g/cm3,μ=24.610 mm-1,F（000）=644,the final R=0.0381 and wR=0.1176 for 1465 observed reflections with I 〉 2σ（I）.The complex presents a 2D-layered structure featuring two different types of rings,and has a （4,36）topology based on Pb and butca4-nodes.In solid state,complex 1 shows photoluminescence with the maximum emission intensity at 468 nm under 286 nm excitation.

Electrochemical Determination of Trace Amounts of Lead (Ⅱ) and Cadmium (Ⅱ) at a Calix[6]arene Modified Carbon Paste Electrode

An electrochemical method for the simultaneous determination of lead(II) and Cadmium(II) with a calix[6]arene modified carbon paste electrode (CPE) has been developed. Pb2+ and Cd2+ were accumulated at the surface of the modified electrode via formation of chemical complexes with calix[6]arene, and reduced at 1.40 V. During the following anodic potential sweep, reduced lead and cadmium were oxidized, and two well-defined striping peaks appeared at about ?0.60 V and ?0.84 V. Compared with a bare carbon paste electrode, the calix[6]arene modified CPE greatly improves the sensitivity of determining lead and cadmium. The stripping peak currents change linearly with the concentration of Pb2+ 3.0×10?8–8.0×10?6 mol·L?1 and with that of Cd2+ 6.0×10?8–1.0×10?5 mol ·L?1. The detection limits of Pb2+ and Cd2+ are found to be 8.0×10?9 mol·L?1 and 2.0×10?8 mol·L?1, respectively. The modified carbon paste electrode was applied to determine trace levels of lead and cadmium in water samples. Comparing with that of atomic absorption spectrometry, the results suggests that the calix[6]arene modified CPE has great potential for the practical sample analysis. Key words lead(II) - cadmium(II) - calix[6]arene - differential pulse stripping voltammetry - chemically modified electrode CLC number O 657.15 Foundation item: Supported by the National Natural Science Foundation of China (60171023)Biography: JI Xiao-bo (1980-), male, Master, research direction: electroanalytical chemistry.

SiO2 nanoparticle-regulated crystallization of lead halide perovskite and improved efficiency of carbon-electrode-based low-temperature planar perovskite solar cells

SiO2 nanoparticles were used to regulate the crystallizing process of lead halide perovskite films prepared by the sequential deposition method,which was used in the low-temperature-processed,carbon-electrode-basing,hole-conductor-free planar perovskite solar cells.It was observed that,after adding small amount of SiO2 precursor(1 vol%)into the lead iodide solution,performance parameters of open-circuit voltage,short-circuit current and fill factor were all upgraded,which helped to increase the power conversion efficiency(reverse scan)from 11.44(±1.83)%(optimized at 12.42%)to 14.01(±2.14)%(optimized at 15.28%,AM 1.5G,100 mW/cm^2).Transient photocurrent decay curve measurements showed that,after the incorporation of SiO2 nanoparticles,charge extraction was accelerated,while transient photovoltage decay and dark current curve tests both showed that recombination was retarded.The improvement is due to the improved crystallinity of the perovskite film.X-ray diffraction and scanning electron microscopy studies observed that,with incorporation of amorphous SiO2 nanoparticles,smaller crystallites were obtained in lead iodide films,while larger crystallites were achieved in the final perovskite film.This study implies that amorphous SiO2 nanoparticles could regulate the coarsening process of the perovskite film,which provides an effective method in obtaining high quality perovskite film.