Unveiling the key factor affecting the illumination deterioration and response measures for lead halide perovskite solar cells

So far,it's been widely acknowledged that the Pb I2decomposition under illumination mainly accounts for the degradation of perovskite solar cells(PSCs)under maximum power point(MPP)tracking condition.However,PSCs without excess Pb I2were also reported to deteriorate rapidly under the same condition.Here,we demonstrate that the key to enhance PSCs stability under MPP tracking condition is not to have fascinating surface morphology with effective suppression of nonradiative recombination traps but to prevent the migration of iodine ion(I-)under light illumination.By partially substituting methylammonium chloride(MACl)with methylammonium iodide(MAI)and simutaneouly introducing I2during the sequential deposition,the iodine vacancies in perovskite films are substantially suppressed,thereby limiting the pathways for I^(-)migration.As a consequence,PSCs with efficiency of 24.28%are fabricated with remarkably enhanced working stability.

Production of Superoxide Ion with Carbon Gas-Diffusion-Electrode And Reaction of Superoxide Ion with Aromatic Halide

Superoxide ion O^-_2 is prepared in aprotic media by carbon gas-diffusion-electrode for the first time. The experimental results indicate that this electrode is superior to carbon plane-electrode in the reaction of O^-_2 with p-bromonitrobenzene. When the gas-diffussion-electrode is used, the yield of the product nitrophenol increases by 20%, and the selectivity of the reaction is nearly doubled as compared with the plane-electrode.

Electrocatalytic Synthesis of Propylene Carbonate from CO_2 and Propylene Oxide

The electrocatalytic synthesis of propylene carbonate（PC） from CO2 and propylene oxide（PO） was studied under mild conditions（PCO2=1.01×105 Pa, t=25 ℃）. Influences of solvents, supporting electrolytes, the passed charge, the nature of electrodes and the current density（j） on the yield of PC were investigated to optimize the electrolytic conditions, with the maximal yield to be 46.2%, the selectivity of propylene carbonate is 100%. The reduction of propylene oxide in the absence and presence of CO2 was examined by cyclic voltammetry. The mechanism of the reaction initiated by the synergistic effect of halides ions of supporting electrolytes with nucleophilicity and the metal ions from scarification anode with Lewis acid acidity was proposed on the basis of our results.

Interfacial stabilization for inverted perovskite solar cells with long-term stability

Perovskite solar cells(PSCs)commonly exhibit significant performance degradation due to ion migration through the top charge transport layer and ultimately metal electrode corrosion.Here,we demonstrate an interfacial management strategy using a boron chloride subphthalocyanine(Cl_(6)SubPc)/fullerene electron-transport layer,which not only passivates the interfacial defects in the perovskite,but also suppresses halide diffusion as evidenced by multiple techniques,including visual element mapping by electron energy loss spectroscopy.As a result,we obtain inverted PSCs with an efficiency of 22.0%(21.3%certified),shelf life of 7000 h,T_(80) of 816 h under damp heat stress(compared to less than 20 h without Cl_(6)SubPc),and initial performance retention of 98%after 2000 h at 80℃in inert environment,90%after 2034 h of illumination and maximum power point tracking in ambient for encapsulated devices and 95%after 1272 h outdoor testing ISOS-O-1.Our strategy and results pave a new way to move PSCs forward to their potential commercialization solidly.

Bromide ion mediated modification to digestive ripening process： Preparation of ultra-small Pd, Pt, Rh and Ru nanoparticles

Nanoparticles of catalytically important transition metals, such as Pd, Pt, Rh, and Ru have been prepared by the well-known ＂digestive ripening＂ （DR） and ＂modified digestive ripening＂ （mDR） methods. In the traditional DR process, a polydisperse colloidal dispersion is refluxed in the presence of a surface-active molecule, such as alkanethiol. The mDR method involved a small modification in the procedure, wherein refluxing was performed with an alkanethiol and a tetra-alkylammonium bromide surfactant. This minor modification led to a dramatic change in the final particle size distributions, giving access to nano- particles in the 〈3 nm size regime; this was not possible with the traditional DR process. Bromide ions, which are present during refluxing, proved to be an important ingredient in the modification process. These bromide ions are revealed to act as etchants, resulting in ultra-small nanoparticles. All transition metal nanoparticles investigated displayed catalytic activity in the reduction reaction of p-nitro phenol. Pd nanoparticles, synthesized by a modified digestive ripening method, exhibited the best catalytic activity among the systems investigated.

Reviewing the impact of halides on electrochemical CO_(2) reduction

Electrochemical CO_(2) reduction reaction(CO_(2)RR)is a promising technology for mitigating global warming and storing renewable energy.Designing low-cost and efficient electrocatalysts with high selectivity is a priority to facilitate CO_(2) conversion.Halide ion(F^(-),Cl^(-),Br^(-),I^(-))modified electrocatalysts is a potential strategy to promote CO_(2) reduction and suppress the competitive hydrogen evolution reaction(HER).Therefore,a comprehensive review of the role and mechanism of halide ions in the CO_(2)RR process can help better guide the future design of efficient electrocatalysts.In this review,we first discuss the role of halide ions on the structure and morphology of electrocatalysts.Secondly,the relationship between the halide ions and the valence states of the active sites on the catalyst surface is further elaborated on.Thirdly,the mechanisms of halide in enhancing CO_(2) conversion efficiency are also summarized,including the involvement of halide ions in electron transfer and their influence on the reaction pathway.Finally,we conclude with a summary and future outlook.