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Nongeminate Radiative Recombination of Free Charges in Cation-Exchanged PbS Quantum Dot Films
Using photoluminescence (PL) spectroscopy we explore the radiative recombination pathways in PbS quantum dots (QDs) synthesized by two methods. We compare conventionally synthesized PbS from a PbO precursor to PbS synthesized using cation-exchange from CdS QDs. We show that strongly coupled films of PbS QDs from the cation-exchange luminesce with significant efficiency at room temperature. This is in stark contrast to conventional PbS QDs, which have exceedingly weak room temperature emission. Moreover, the power dependence of the emission is quadratic, indicating bimolecular radiative recombination that is reasonably competitive with trap-assisted recombination, a feature previously unreported in coupled PbS QD films. We interpret these results in terms of a greatly reduced defect concentration for cation-exchanged QDs that mitigates the influence of trap-assisted recombination. Cation-exchanged QDs have recently been employed in highly efficient and air-stable lead chalcogenide QD devices, and the reduced number of trap states inferred here may lead to improved current collection and higher open circuit voltage.
Evidence for Charge-Transfer Mediation in the Primary Events of Singlet Fission in a Weakly Coupled Pentacene Dimer
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Evidence for reduced charge recombination in carbon nanotube/perovskite-based active layers
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Enhancing Faradaic Charge Storage Contribution in Hybrid Pseudocapacitors
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Time-resolved X-ray photoelectron spectroscopy techniques for the study of interfacial charge dynamics
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Surface charge effect of nanogel on emulsification of oil in water for fossil energy recovery
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Growth of YbFe2O4 single crystals exhibiting long-range charge order via the optical floating zone method
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Oxygen-redox reactions in LiCoO2 cathode without O-O bonding during charge-discharge
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Photovoltaic and charge transfer analysis of perylene diimide dimer systems
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Development of a positively charged nanofiltration membrane for use in organic solvents
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Effect of fixed charge group concentration on salt permeability and diffusion coefficients in ion exchange membranes
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