Route to Improving Photovoltaics Based on CdSe/CdSexTe1-x Type-II Heterojunction Nanorods: The Effect of Morphology and Cosensitization on Carrier Recombination and Transport

Sangheon Lee, Joseph C. Flanagan, Byungho Lee, Taehyun Hwang, Jaewook Kim, Bumjin Gil, Moonsub Shim, Byungwoo Park

Research output: Contribution to journalArticlepeer-review

Abstract

One-dimensionally elongated nanoparticles with type-II staggered band offset are of potential use as light-harvesting materials for photovoltaics, but only a limited attention has been given to elucidate the factors governing the cell performance obtainable from such materials. Herein, we describe a combined strategy to enhance charge collection from CdSe/CdSexTe1-x type-II heterojunction nanorods (HNRs) utilized as light harvesters for sensitized solar cells. By integrating morphology- and composition-tuned type-II HNRs into solar cells, factors that yield interfaces favorable both for the electron injection into TiO2 and hole transfer to electrolyte are examined. Furthermore, it is shown that a more efficient photovoltaic system results from cosensitization with CdS quantum dots (QDs) predeposited on a TiO2 scaffold, which improves charge collection from HNRs. Electrochemical impedance spectroscopy (EIS) analysis suggests that such a synergistically enhanced system benefits from the decreased recombination within HNRs and facilitated charge transport through the cosensitized TiO2 electrode, even with the activation of a recombination path presumably related to the photogenerated holes in CdS QDs.

Original languageEnglish (US)
Pages (from-to)31931-31939
Number of pages9
JournalACS Applied Materials and Interfaces
Volume9
Issue number37
DOIs
StatePublished - Sep 20 2017

Keywords

  • II-VI semiconductors
  • charge collection
  • nanorods
  • sensitized solar cells
  • type-II heterojunction

ASJC Scopus subject areas

  • Materials Science(all)

Fingerprint

Dive into the research topics of 'Route to Improving Photovoltaics Based on CdSe/CdSe<sub>x</sub>Te<sub>1-x</sub> Type-II Heterojunction Nanorods: The Effect of Morphology and Cosensitization on Carrier Recombination and Transport'. Together they form a unique fingerprint.

Cite this