High Seebeck Coefficient in Solution-Grown PbS Films

We have investigated the Seebeck coefficient of solution-grown lead sulfide (PbS) films at room temperature. A high Seebeck coefficient of 450 μ V/K was observed, which is over three times the value commonly measured for PbS films. The positive sign of the Seebeck coefficient indicates that the measured film was characteristically p -type. The high sheet resistance of the films, ∼186 kΩ/sq., suggests that the high Seebeck coefficient may be the result of increased contributions from junctions and boundary scattering of carriers occurring at interfaces between nanocrystallites, consistent with the scanning electron microscopy study of the film morphology. The solution-grown PbS technology employed here is inherently scalable and, with the larger Seebeck coefficient, may be well suited for energy-harvesting applications.