We observe that a reasonable elongation (element ratio of 6-7) of PbSe NCs can cause as much as an somewhere around two-fold increase while in the multiexciton yield compared to spherical nanoparticles. The improved Auger lifetimes and enhanced charge transport properties frequently assodated with elongated nanostructures recommend that lead chalcogenide nanorods really are a promising system for testing CM concepts in sensible photovoltaics.
Historically, experimental concerns are already an important aspect influencing CM studies. To this end, we talk about the purpose of NC photocharging in CM measurements. Photodiarging can distort multiexciton dynamics, resulting in erroneous estimations of the CM yield. Right here, we demonstrate that on top of that to distorting time-resolved CM signals, photocharging also creates spectral signatures that mimic CM.
This re-emphasizes the importance of a cautious analysis with the probable result of charged species in each optical and photocurrent-based measurements of this procedure."
"Recent reports of multiexciton generation (MEG), a approach by which one absorbed photon generates numerous excitons, in lead dialcogenide nanocrystals (NCs) have intensified investigation interest in using this phenomenon to improve the efficiency of solar vitality conversion. Useful implementation of MEG processes in solar cells and solar-to-fuel conversion gadgets calls for the growth of components with larger MEG efficiencies and reduce excitation thresholds than are at this time available, at the same time as schemes for efficient multiexciton extraction prior to the ultrafast exciton-exciton annihilation occurs.
This Account focuses about the extraction of multiexcitons by interfadal electron transfer in model NC-molecular acceptor complexes. We offer an overview of multiexciton annihilation and multiexciton dissociation (MW) processes in NC-acceptor complexes of (i) CdSe quantum dots (QDs), (ii) CdSe/CdS quasi-type II core/shell QDs, (iii) CdSe quantum confined nanorods (QRs), and (iv) PbS QDs. We present that ultrafast electron transfer to adsorbed molecular acceptors can efficiently dissociate multiexcitons produced by absorption of many photons in (i), (ii), and (iii). In contrast to core-only CdSe QDs, the electron hole distributions in CdSe/CdS quasi-type II QDs and CdSe QRs appreciably enhance their MED efficiencies by simultaneously retarding Auger recombination and facilitating interfadal electron transfer.
Last but not least, in PbS-methylene blue (MB+) complexes, we present the presence of electron acceptors dots not impact the MEG efficiency and electron transfer to MB+ efficiently dissociates the many excitons created in PbS QDs. Our findings demonstrate that ultrafast interfacial charge transfer might be an productive approach for extracting multiexcitons, and wavefunction engineering in quantum confined NCs can even further boost MED efficiency.