Nonplasmonic Hot‐Electron Photocurrents from Mn‐Doped Quantum Dots in Photoelectrochemical Cells. Issue 5 (2nd February 2016)

• Record Type: Journal Article
• Authors: Dong, Yitong; Rossi, Daniel; Parobek, David; Son, Dong Hee
• Is Part Of: Chemphyschem. Volume 17:Issue 5(2016)
• Page Start: 660
• Page End: 664
• Publication Date: 2016-02-02
• Subjects: colloids -- doping -- hot electron current -- photoelectrochemistry -- quantum dots; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201501142
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: We report the measurement of the hot‐electron current in a photoelectrochemical cell constructed from a glass/ITO/Al2 O3 (ITO=indium tin oxide) electrode coated with Mn‐doped quantum dots, where hot electrons with a large excess kinetic energy were produced through upconversion of the excitons into hot electron hole pairs under photoexcitation at 3 eV. In our recent study ( J. Am. Chem. Soc .2015, 137, 5549), we demonstrated the generation of hot electrons in Mn‐doped II–VI semiconductor quantum dots and their usefulness in photocatalytic H2 production reaction, taking advantage of the more efficient charge transfer of hot electrons compared with band‐edge electrons. Here, we show that hot electrons produced in Mn‐doped CdS/ZnS quantum dots possess sufficient kinetic energy to overcome the energy barrier from a 5.4–7.5 nm thick Al2 O3 layer producing a hot‐electron current in photoelectrochemical cell. This work demonstrates the possibility of harvesting hot electrons not only at the interface of the doped quantum dot surface, but also far away from it, thus taking advantage of the capability of hot electrons for long‐range electron transfer across a thick energy barrier. Abstract : Hot results : The upconversion of excitons into hot‐electron hole pairs in Mn‐Doped CdS/ZnS quantum dots is used to generate hot electrons with enough excess energy to overcome the potential barrier of a 7.5nm thick aluminum oxide film. The measured photocurrent through the aluminum oxide film demonstrates the potential of this system for long‐range charge transport.