Generation of hot carrier population in colloidal silicon quantum dots for high-efficiency photovoltaics

Pengfei Zhang, Yu Feng, Xiaoming Wen, Wenkai Cao, Rebecca Anthony, Uwe Kortshagen, Gavin Conibeer, Shujuan Huang

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Hot carrier generation in silicon (Si) quantum dots (QDs) is studied with power dependent continuous wave photoluminescence (CWPL) spectroscopy. By taking sub-band gap absorption into account, a modified Maxwell-Boltzmann-form equation was employed to achieve accurate theoretical fitting to the CWPL spectra of the Si QDs. As a fitting parameter, the excited carrier temperature was calculated. A steady-state carrier population was revealed with a temperature 500 K above room temperature under illumination equivalent to one standard sun (100 mW/cm2). In addition, sice the carrier temperature increased with the power of illumination, a state filling effect is proposed as a reasonable cause for the elevated carrier temperature by comparative study of the CWPL spectra of Si QDs with three different sizes. These Si QDs show great potential for one of the steps towards a practical hot carrier solar cell (HCSC) device as high carrier temperatures can be achieved by state filling under mild illumination.

Original languageEnglish (US)
Pages (from-to)391-396
Number of pages6
JournalSolar Energy Materials and Solar Cells
Volume145
DOIs
StatePublished - Feb 1 2016

Keywords

  • Hot carrier solar cell
  • Photoluminescence
  • Silicon quantum dots
  • State filling

How much support was provided by MRSEC?

  • Partial

Reporting period for MRSEC

  • Period 2

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