Multi-site Passivation of ZnO Metal Oxides via Biomolecules for Efficient and Highly Stable Organic Solar Cells

ZnO nanoparticles(nps)among metal oxide(MOs)are proven to be essential electron transporting layers(ETLs)applied in organic solar cells(OSCs).However,intrinsic defects,interfacial charge recombination,and catalytic behavior towards the active layer restrict the applications of ZnO nps for efficient and long-term stable OSCs.The commonly available biomolecule cytidine 5'-monophosphate(CMP-OH)with phosphonic acid,its salt cytidine 5'-monophosphate disodium salt(CMP-ONa)with a phosphate group as an anchoring group and conjugated terminal functional in both analogous molecules provide carrier transfer bridge at bottom interface of the active layer.Systematized theoretical investigations and characterizations have discovered the multi-site coordination of CMP-OH towards acceptor molecules and ZnO nps.The dual-side alignment of CMP analogous molecules hinders interfacial charge recombination and enhances charge transfer potential at once.Inevitably,PM6:L8-BO-based OSCs with modified ETL obtain 18.13%efficiency,12%higher than that of unmodified nps.Besides higher efficiency,CMP-OH-based OSC devices illustrate remarkably improved thermal stability for 500 h at 85℃with 72%of initial PCE and operation stability for 2000 h with 90.1%of initial PCE.This work reveals the passivation mechanism of multi-anchoring groups towards MOs and single-functional groups towards the active layer to optimize the interface for efficient and highly stable OSCs.

Improving Both Electron and Hole Mobilities of an Ambipolar Polymer by Integrating Sodium Sulfonate-Tethered Alkyl Side Chains

of main observation and conclusion High performance ambipolar organic semiconductors are highly desirable for organic logic circuits.Herein,we demonstrate the integration of sodium sulfonate(SS)-tethered sidechains into a diketopyrrolopyrrole-based ambipolar polymer(PDPP3T)can simultaneously improve its hole and electron transport performances either parallel or perpendicular to polymer film.Three SS-functionalized polymers(PDPP3T-XSS,x=0.025,0.05 and 0.10)were synthesized and studied.It was found that SS functionalization can reinforce interchain n-Ti interactions,slightly lower frontier orbital energy levels,produce more rod-like structures in film,and change chain-packing from edge-on to face-on fashion,but has little influence on thermal properties.More interestingly,organic field-effect transistors reported hole mobility of 0.27±0.066 cm^2.V^-1·s^-1 and electron mobility of 0.038±0.016 cm^2.V^-1·s^-1 for PDPP3T,while increased 2.4 and 5 folds to 0.64±0.087 and 0.19±0.051 cm^2.V^-1·s^-1 for PDPP3T-0.025SS,respectively.Moreover,PDPP3T-xSS devices displayed reduced threshold voltages for both hole and electron transports.Meanwhile,space charge-limited current method found SS functionalization achieved an order of magnitude increase in electron mobility and slight enhancement in hole mobility transporting perpendicular to polymer film.In-depth investigations suggest such enhancements may originate from the joint actions of chain-stacking modulation and ionic doping effect.