Nonmonotonic Size-Dependent Carrier Mobility in PbSe Nanocrystal Arrays

• DOI: 10.1021/jz300035t
• Publication Date: 2012-02-27T21:43:33Z
• Authors: Jihye Lee; One Choi; Eunji Sim
• Keywords: Electron Mobility; Electrical mobility; Charge carrier

On the basis of a tight binding system-bath model, we investigated carrier mobility PbSe nanocrystal (NC) arrays as function NC size and inter-NC separation. The size-dependent trend calculated mobilities are in excellent agreement with recent experimental measurements: electron increased up to diameter ∼6 nm then decreased for larger NCs, whereas hole showed monotonic size-dependency. Carrier increase was associated reduced activation energy that governs charge-transfer processes. In contrast, decrease large NCs found be due smaller electronic coupling. Control separation is crucial enhancement: may change by an order magnitude when varies little 1 2 Å. We anticipate similar size-dependency other semiconductor arrays, although crossover which reaches its maximum depends on material.