Low-cost polymer acceptors with noncovalently fused-ring backbones for efficient all-polymer solar cells

The polymerization of fused-ring acceptors(FRAs) to afford their corresponding polymeric acceptors for high-performance all-polymer solar cells(all-PSCs) has achieved remarkable progress in the past few years.However,due to the high degree of synthetic complexity for the monomer,the high-cost of these polymeric acceptors may limit their commercial applications.Thus,it is urgent to develop inexpensive and high-performance polymeric acceptors for all-PSCs.Herein,two novel polymeric acceptors(PBTzO and PBTzO-2F) have been designed and synthesized by copolymerization of noncovalently fused ring acceptors(NFRAs),which were employed in all-PSCs for the first time.Upon introducing the “noncovalently conformational locks(NoCLs)” in the backbone and selective fluorination of the end-group,photophysical and electrical properties,and solidstate packing properties of the NFRAs have been rationally tuned.As a result,the PBDB-T:PBTzO-2F based devices presented an excellent power conversion efficiency(PCE) of 11.04%,much higher than that of PBTzO based ones due to the increased charge generation and extraction,improved hole transfer and carrier mobilities,and reduced energy loss.More importantly,PBTzO-2F exhibited a much lower synthetic complexity(SC) index and higher figure-of-merit(FOM) values than the high-performance fused-ring acceptor based polymer acceptors(FRA-PAs) due to the simpler structures and more effective synthesis.This contribution provided a novel idea to achieve low-cost and high-performance all-PSCs.

Non-contact biomimetic mechanism for selective hydrogenation of nitroaromatics on heterogeneous metal nanocatalysts

While the enzymatic reduction of unsaturated compounds usually has high specificity,highly selective reduction processes are hardly realized by heterogeneous industrial catalysts,which is critical for the green production of many fine chemicals.Here,we report an unexpected discovery of a biomimetic behavior of dicyandiamide(DICY)-modified Pt nanocatalysts for the green hydrogenation of a wide range of nitroaromatics.We demonstrate that the surface modification by DICY not only prevents the direct contact of nitroaromatic reactants with Pt surface but also induces an effective non-contact hydrogenation mechanism mediated by protons and electrons.In such a process,the DICY layer serves as a“semi-permeable membrane”to allow the permeation of H_(2) molecules for being activated into electrons and protons at the Pt-DICY interface.With the generation of separated protons and electrons,the nitro group with strong electrophilic properties can be hydrogenated through the electron transfer followed by the proton transfer,which is facilitated by the hydrogen bonding network formed by protonated DICY.The unique mechanism makes it highly directional toward the hydrogenation of nitro groups without side reactions.Owing to its capability to largely eliminate the waste generation,the developed Pt-DICY catalysts have been successfully applied for the green industrial production of many important aniline intermediates.