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Volumn 10, Issue 6, 2010, Pages 2049-2057

Apparent versus true carrier multiplication yields in semiconductor nanocrystals

Author keywords

Auger recombination; Carrier multiplication; Charge separation; Charged exciton; PbSe nanocrystals; Time resolved photoluminescence

Indexed keywords

AUGER RECOMBINATION; CARRIER MULTIPLICATION; CHARGE SEPARATIONS; CHARGED EXCITONS; PBSE NANOCRYSTALS; TIME-RESOLVED PHOTOLUMINESCENCE;

EID: 77953303309     PISSN: 15306984     EISSN: 15306992     Source Type: Journal    
DOI: 10.1021/nl100177c     Document Type: Article
Times cited : (207)

References (45)
  • 35
    • 77953307156 scopus 로고    scopus 로고
    • note
    • 3.
  • 37
    • 77953308594 scopus 로고    scopus 로고
    • note
    • In the case of Poisson statistics, for an average degree of photocharging of 0.25 the fraction of doubly charged NCs is only ∼2%. The actual fraction of such NCs should be even lower as the existence of one charge in a NC complicates the introduction of the second charge because of an additional Coulombic barrier. This effect is expected to lower the probability of double charging compared to that for Poisson statistics.
  • 38
    • 77953301660 scopus 로고    scopus 로고
    • note
    • The assumption that the efficiency of CM is the same in charged and neutral NCs is at odds with the results of a recent computation (ref 39) but is supported by the fact that this assumption produces good quantitative agreement between the CM results for stirred samples and the true CM efficiencies extracted from the apparent CM yields in static measurements. Another piece of evidence that photocharging does not suppress CM is the appearance in static samples of a PL relaxation component faster than that of a neutral biexciton when the corresponding stirred sample only shows decay characteristic of neutral biexcitons.
  • 40
    • 77953311833 scopus 로고    scopus 로고
    • note
    • The derivation of the degree of photocharging from time-integrated PL measurements is based on the assumption that the Auger lifetime of charged species (excitons and biexcitons) is much shorter than their radiative decay times, and hence, the time-integrated signal is dominated by emission from neutral NCs. Indeed, we always observe a reduction in time-integrated emission intensity upon stopping the stirring of samples that show a static-stirred difference in PL dynamics. Further, we see good quantitative agreement between fractional changes in the time-integrated PL and long-time PL signals measured by PL up-conversion.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.