We report the synthesis of colloidal InAs/ZnSe core/shell quantum dots (QDs) by the hot injection method. InAs nanocrystals have a narrow band gap of 0.38 eV, a high absorption coefficient, and multiple exciton generation; hence, they are promising candidates for application in solar cells. However, poor coverage of the titania layer causes a low solar efficiency of 1.74%. We synthesized type-I InAs/ZnSe core/shell QDs as an effective solution; they are expected to have enhanced solar cell efficiency because of the different wettability of the ZnSe shell and their superior stability as compared to that of the unstable InAs core. We characterized the QDs by powder X-ray diffraction, transmission electron microscopy, and absorption and emission spectroscopy. The particle size increased from 2.6 nm to 5 nm, whereas the absorption and emission spectra exhibited a slight red shift, which is typical of type-I structured core/shell QDs. We then fabricated QD-based solar cells and investigated the cell properties, obtaining an open-circuit voltage (VOC) of 0.51 V, a short-circuit current density (JSC) of 12.4 mA/cm2, and a fill factor (FF) of 44%; the efficiency of 2.7% shows an improvement of more than 50% as compared to the values in previous reports.
Bibliographical noteFunding Information:
This work was supported by the New & Renewable Energy Core Technology Program of Korea Institute of Energy Technology Evaluation and Planning (KETEP) (no. 201330300001 ) and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (no. 2014R1A5A1009799 ), Republic of Korea.
© 2015 Elsevier B.V. All rights reserved.
- InAs/ZnSe core/shell
- Quantum dot based solar cell
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Computer Science(all)
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Electrical and Electronic Engineering