Polymer/quantum dot nanostructures in remarkably stabilized photovoltaics based on polymers having benzodithiophene/naphthothiadiazole constituents

Supramolecular structures were developed by the graphene and carbon quantum dots (GQD and CQD) and poly[benzodithiophene-bis(decyltetradecyl-thien) naphthothiadiazole] (PBT-DNT) short/long chains. The pre-developed quantum dot (QD)/conjugated polymer-based supramolecules were used as promoting agents of efficacy and stability in the PBT-DNT:[6,6]-phenyl C71 butyric acid methyl ester (PC71BM) photovoltaics. Air aging experiments were carried out in 38% humidity at 36 degrees C within the time periods of 0 to 90 days with 1 month intervals. The CQD and GQD nanoparticles and their associated structures by PBT-DNT long backbone did not conspicuously alter the performance and stability of PBT-DNT:PC71BM systems. Within 3 months aging, the power conversion efficiencies fell down from 3.81% to 0.18% for CQD/PBT-DNT long chain and from 4.33% to 0.17% for GQD/PBT-DNT long chain-based systems. In contrast, the patterned GQD/PBT-DNT short chain and CQD/PBT-DNT short chain supramolecules properly played their roles and reflected the best non-aged (5.57% (342 omega cm(2)) and 4.59% (486 omega cm(2))) and 90-day aged (2.01% (764 omega cm(2)) and 1.00% (835 omega cm(2))) photovoltaics. Shorter backbones had a better chance to be arranged onto the QD nanoparticles. The GQD-based nano-hybrids acted better than the CQD-based ones. It could be assigned to the flat and disc-like structure of GQDs, which facilitated assembling of the conjugated chains via pi stacking.

Automated summary

The study developed supramolecular structures using graphene and carbon quantum dots and conjugated polymer chains, finding that GQD/PBT-DNT short chain and CQD/PBT-DNT short chain systems performed the best, while long chain systems had poorer performance. Shorter chains had a better chance of arranging on quantum dot nanoparticles, with GQD-based nano-hybrids outperforming CQD-based ones due to their flat and disc-like structure enabling better assembly of conjugated chains.