Ultrafast charge-and energy-transfer dynamics in conjugated polymer: Cadmium selenide nanocrystal blends

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

  • Frederik S.F. Morgenstern - , University of Cambridge (Autor:in)
  • Akshay Rao - , University of Cambridge (Autor:in)
  • Marcus L. Böhm - , University of Cambridge (Autor:in)
  • René J.P. Kist - , University of Cambridge (Autor:in)
  • Yana Vaynzof - , University of Cambridge (Autor:in)
  • Neil C. Greenham - , University of Cambridge (Autor:in)

Abstract

Hybrid nanocrystal-polymer systems are promising candidates for photovoltaic applications, but the processes controlling charge generation are poorly understood. Here, we disentangle the energy-and charge-transfer processes occurring in a model system based on blends of cadmium selenide nanocrystals (CdSe-NC) with poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4- phenylene vinylene] (MDMO-PPV) using a combination of time-resolved absorption and luminescence measurements. The use of different capping ligands (n-butylamine, oleic acid) as well as thermal annealing allows tuning of the polymer-nanocrystal interaction. We demonstrate that energy transfer from MDMO-PPV to CdSe-NCs is the dominant exciton quenching mechanism in nonannealed blends and occurs on ultrafast time scales (<1 ps). Upon thermal annealing electron transfer becomes competitive with energy transfer, with a transfer rate of 800 fs independent of the choice of the ligand. Interestingly, we find hole transfer to be much less efficient than electron transfer and to extend over several nanoseconds. Our results emphasize the importance of tuning the organic-nanocrystal interaction to achieve efficient charge separation and highlight the unfavorable hole-transfer dynamics in these blends.

Details

OriginalspracheEnglisch
Seiten (von - bis)1647-1654
Seitenumfang8
FachzeitschriftACS nano
Jahrgang8
Ausgabenummer2
PublikationsstatusVeröffentlicht - 25 Feb. 2014
Peer-Review-StatusJa
Extern publiziertJa

Schlagworte

Ziele für nachhaltige Entwicklung

Schlagwörter

  • CdSe, charge transfer, hybrid, nanocrystals, photoluminescence, photovoltaics, polymer, transient absorption