Nonmonotonic size-dependent carrier mobility in PbSe nanocrystal arrays

Jihye Lee, One Choi, Eun Ji Sim

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

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

Original languageEnglish
Pages (from-to)714-719
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume3
Issue number6
DOIs
Publication statusPublished - 2012 Mar 15

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Carrier mobility
carrier mobility
Nanocrystals
nanocrystals
Electron mobility
electron mobility
Hole mobility
hole mobility
lead selenide
Charge transfer
baths
crossovers
Activation energy
charge transfer
Semiconductor materials
activation energy
trends
augmentation
electronics

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

Cite this

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

In: Journal of Physical Chemistry Letters, Vol. 3, No. 6, 15.03.2012, p. 714-719.

Research output: Contribution to journalArticle

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