An Efficient Trap Passivator for Perovskite Solar Cells:Poly(propylene glycol)bis(2‑aminopropyl ether)

Perovskite solar cells(PSCs)are regarded as promising candidates for future renewable energy production.High-density defects in the perovskite films,however,lead to unsatisfactory device performances.Here,poly(propylene glycol)bis(2-aminopropyl ether)(PEA)additive is utilized to passivate the trap states in perovskite.The PEA molecules chemically interact with lead ions in perovskite,considerably passivate surface and bulk defects,which is in favor of charge transfer and extraction.Furthermore,the PEA additive can efficiently block moisture and oxygen to prolong the device lifetime.As a result,PEA-treated MAPbI3(MA:CH3NH3)solar cells show increased power conversion efficiency(PCE)(from 17.18 to 18.87%)and good longterm stability.When PEA is introduced to(FAPbI3)1-x(MAPbBr3)x(FA:HC(NH2)2)solar cells,the PCE is enhanced from 19.66 to 21.60%.For both perovskites,their severe device hysteresis is efficiently relieved by PEA.

Synthesis of carbon frameworks with N,O and S-lined pores from gallic acid and thiourea for superior CO2 adsorption and supercapacitors

"C2N"-species have emerged as a promising material with carbon-like applications in sorption,gas separation and energy storage,while with much higher polarity and functionality.Controlled synthesis of"C2N"structure is still based on complex and less-sustainable monomers,which prohibits its broader industrial application.Here we report a class of well-defined C2(NxOySz)1 carbons with both high content of N/O/S heteroatoms and large specific surface area of up to 1704 m^2 g^-1,which can be efficiently synthesized through a simple additive condensation process using simple gallic acid and thiourea as the building blocks,without subtractive activation.This 1,4-para tri-doped C2(NxOySz)1 structure leads to sufficient CO2 adsorption capacity(3.0 mmol g^-1 at 273 K,1 bar)and a high CO2/N2 selectivity(47.5 for a 0.15/0.85 CO2/N2 mixture at 273 K).Related to the polarity,the polar frameworks can be used as supercapacitor electrodes,with record specific capacitances as high as 255 F g^-1 at 3.5 V for a symmetric supercapacitor in ionic liquid electrolyte.This work discloses a general way for preparing a novel family of multifunctional,high heteroatomdoped porous materials for various applications.

A second-order nonlinear optical dendronized hyperbranched polymer containing isolation chromophores： achieving good optical nonlinearity and stability simultaneously

Large nonlinear optical(NLO) coefficient and good stability, two essential factors to evaluate second-order NLO materials, are difficult to be achieved in one molecule simultaneously. Herein, by utilizing the concept of "isolation chromophore", "isolation group" and dendritic structure, a dendritic molecule D-NS and a dendronized hyperbranched polymer DHP-NS are prepared to investigate their structure-property relationship. For the small dendritic molecule D-NS, it exhibits a high d33 value of 140 pm/V.But this value can be easily dropped when the temperature is higher than 50 °C, which extremely limits its real application. After introducing D-NS into a dendronized hyperbranched polymer chains, the obtained DHP-NS also shows a high d33 value of101 pm/V, but much better stability than D-NS. Even when its thin film was heated to 120 °C, no obvious decay can be observed in the d33 value of DHP-NS. This work demonstrates an effective strategy to realize both large NLO effect and good stability simultaneously.