A novel perylene diimide-based ionene polymer and its mixed cathode interlayer strategy for efficient and stable inverted perovskite solar cells

Inverted(p-i-n)perovskite solar cells(PerSCs)have attracted much attention owing to their low temperature processability,less hysteresis effect and easy integration as a subunit for the tandem device.The unsatisfactory interface contacts and energy level barrier between adjacent interlayers on the cathode side are one of the key challenges for the development of p-i-n PerSCs.Herein,perylene diimidebased(PDI)ionene polymer was synthesized and developed as a cathode interlayer(CIL)to enhance interface contact,reduce the energy level barrier and prevent the migration of I-ions.The compact PNPDI CIL with high conductivity and appropriate lowest unoccupied molecular orbital(LUMO)level,resulted in a high efficiency device(20.03%),which is higher than the control device with bathophenanthroline(Bphen)(19.48%).Bphen-based CIL shows better adjusting ability of the work function of cathode metal but exhibits poor film-forming property.So,the synergistic effect of 1+1>2 can be obtained by combining Bphen and PNPDI into one CIL.As expected,the device performance was further improved by using the mixed CIL of Bphen and PNPDI,and 21.46%power conversion efficiency(PCE)was achieved.What’s more,the compact and hydrophobic mixed CIL dramatically enhanced the resistance to I-ions and moisture,which led to much enhanced device stability.

蔬菜染色再生纸制作的科普实验

本科普实验基于再生纸的制作方法和蔬菜天然色素知识,设计了具有科学性、趣味性和简单易行特点的蔬菜染色再生纸制作实验。此外,本实验还创造性地将蔬菜染色纸和染色纸浆创作成充满趣味性的纸浆画、杯垫、折纸等手工作品。希望能借此科普实验让大众了解再生纸制作的化学原理和天然色素的提取方法,并加强对化学可持续发展理念的实践。

Gold nanoparticles/single-stranded DNA-reduced graphene oxide nanocomposites based electrochemical biosensor for highly sensitive detection of cholesterol

High density and uniform distribution of the gold nanoparticles functionalized single-stranded DNA modified reduced graphene oxide nanocomposites were obtained by non-covalent interaction.The positive gold nanoparticles prepared by phase inversion method exhibited good dimensional homogeneity and dispersibility,which could readily combine with single-stranded DNA modified reduced graphene oxide nanocomposites by electrostatic interactions.The modification of single-stranded DNA endowed the reduced graphene oxide with favorable biocompatibility and provided the preferable surface with negative charge for further assembling of gold nanoparticles to obtain gold nanoparticles/single-stranded DNA modified reduced graphene oxide nanocomposites with better conductivity,larger specific surface area,biocompatibility and electrocatalytic characteristics.The as-prepared nanocomposites were applied as substrates for the construction of cholesterol oxidase modified electrode and well realized the direct electron transfer between the enzyme and electrode.The modified gold nanoparticles could further catalyze the products of cholesterol oxidation catalyzed by cholesterol oxidase,which was beneficial to the enzyme-catalyzed reaction.The as-fabricated bioelectrode exhibited excellent electrocatalytic performance for the cholesterol with a linear range of 7.5–280.5μmol·L^(−1),a low detection limit of 2.1μmol·L^(−1),good stability and reproducibility.Moreover,the electrochemical biosensor showed good selectivity and acceptable accuracy for the detection of cholesterol in human serum samples.

Interface Engineering of Inverted Perovskite Solar Cells Using a Self-doped Perylene Diimide Ionene Terpolymer as a Thickness-Independent Cathode Interlayer

Inverted perovskite solar cells(PerSCs)are a highly promising candidate in the photovoltaic field due to their low-temperature fabrication process,negligible hysteresis,and easy integration with Si-based solar cells.A cathode interlayer(CIL)is necessary in the development of inverted devices to reduce the trap density and energy barrier between the electron transport layer(ETL)and the electrode.However,most CILs are highly thickness-sensitive due to low conductivity and poor film-forming.In this study,we report on a self-doping perylene imide-based ionene polymer(PNPDIN)used as CIL material to modify electrode in inverted PerSCs.PNPDIN exhibits high conductivity and a good solubility in polar solvent,which results in an improved power conversion efficiency(PCE)from 10.05%(device without a CIL)to 16.97%.When the blend of PNPDIN and Bphen was used as a mixed CIL,the PCE of PerSCs can be further increased to 21.28%owing to the excellent morphology and matched energy level.More importantly,the PCE of the device is highly tolerant to the thickness of the mixed CIL,which benefited from the high conductivity of PNPDIN.This development is expected to provide an excellent mixed CIL material for roll-to-roll processing efficient and stable inverted PerSCs.