Production and closed-loop recycling of biomass-based malleable materials

The search of biomass-based substitutes for fossil-based plastics has become a pressing task due to the severe long-term threats of plastic wastes to the ecosystem.However,the development in this area is strongly impeded by the high cost of biomass separation and the poor processability of unseparated biomass.Herein,we demonstrate,for the first time,an efficient and scalable method to generate greener plastics by directly integrating unseparated biomass waste(i.e.,wood powder)with crosslinked covalent adaptable networks.Through a simple compression molding process,the wood biomass and polymer particles can be fused together to form a continuous material,which is endowed with repairability,reprocessibility,and closed-loop full recyclability.The method demonstrated in this work paves the way for largescale industrial production of environmentally friendly biomass-based plastics.

Stretchable transparent electrodes for conformable wearable organic photovoltaic devices

To achieve adhesive and conformable wearable electronics,improving stretchable transparent electrode(STE)becomes an indispensable bottleneck needed to be addressed.Here,we adopt a nonuniform Young’s modulus structure with silver nanowire(AgNW)and fabricate a STE layer.This layer possesses transparency of>88%over a wide spectrum range of 400–1000 nm,sheet resistance below 20Ωsq^(−1),stretchability of up to 100%,enhanced mechanical robustness,low surface roughness,and good interfacial wettability for solution process.As a result of all these properties,the STE enables the fabrication of a highly efficient ultraflexible wearable device comprising of both organic photovoltaic(OPV)and organic photodetector(OPD)parts with high mechanical durability and conformability,for energy-harvesting and biomedical-sensing applications,respectively.This demonstrates the great potential of the integration of OPVs and OPDs,capable of harvesting energy independently for biomedical applications,paving the way to a future of independent conformable wearable OPV/OPDs for different applications.

Self-doped n-type small molecular electron transport materials for high-performance organic solar cells

Two naphthalene diimide （NDI） and perylene diimide （PDI） based n-type water/alcohol soluble small molecules （NFN and PFP） are designed and utilized as electron transport layers （ETLs） for organic solar cells （OSCs）. NFN and PFP are synthesized by using Sonogashira coupling from alkynyl modified fluorene with mono-bromo substituted NDI and PDI. Density functional theory study results of NFN and PFP show that they possess excellent planarity due to the employment of triple bonds as connection units. Moreover, it was shown by electron paramagnetic resonance study that both NFN and PFP possess obvious self-doping behaviors, which may effectively enhance their charge transporting capability as ETLs in OSCs. Power conversion efficiencies of 8.59% and 9.80% can be achieved for OSCs with NFN and PFP as ETLs, respectively. The higher power conversion efficiency （PCE） of PFP based photovoltaic device is originated from the stronger doping property and higher mobility of PFR

n-Type Conjugated Polymer Based on Dicyanodistyrylbenzene and Naphthalene Diimide Units for All-Polymer Solar Cells

All polymer solar cells （all-PSCs）, possessing superior mechanical strength and flexibility, offer the commercialization opportunity of the PSCs for flexible and portable devices. In this work, we designed and synthesized two copolymer acceptors based on dicyanodistyrylbenzene （DCB） and naph-thalene diimide （NDI） units. The corresponding copolymer acceptors are denoted as PDCB-NDI812 and PDCB-NDI1014. The medium band gap copolymer PBDB-T was selected as donor material for investigation of the photovoltaic performance. Two alI-PSCs devices showed power conversion efficiencies （PCE） of 4.26% and 3.43% for PDCB-NDI812 and PDCB-NDI1014, respectively. The improved PCE was ascribed to the higher short-circuit current （Jsc）, greater charge carrier mobility and higher exciton dissociation probability of the PBDB-T：PDCB-NDI812 blend film. These results suggest that DCB unit and NDI unit based copolymer acceptors are promising candidates for high performance alI-PSCs.