The dominant role of exciton quenching in PbS quantum-dot-based photovoltaic devices
Darcy D Wanger1, Raoul E Correa, Eric A Dauler
1Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
Abstract:
We present a quantitative measurement of the number of trapped carriers combined with a measurement of exciton quenching to assess limiting mechanisms for current losses in PbS-quantum-dot-based photovoltaic devices. We use photocurrent intensity dependence and short-wave infrared transient photoluminescence and correlate these with device performance. We find that the effective density of trapped carriers ranges from 1 in 10 to 1 in 10,000 quantum dots, depending on ligand treatment, and that nonradiative exciton quenching, as opposed to recombination with trapped carriers, is likely the limiting mechanism in these devices.
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