Alloying Strategy in Cu-In-Ga-Se Quantum Dots for High Efficiency Quantum Dot Sensitized Solar Cells

Wenxiang Peng; Jun Du; Zhenxiao Pan; Naoki Nakazawa; Jiankun Sun; Zhonglin Du; Gencai Shen; Juan Yu; Jin-Song Hu; Qing Shen; Xinhua Zhong

doi:10.1021/acsami.6b14649

Alloying Strategy in Cu-In-Ga-Se Quantum Dots for High Efficiency Quantum Dot Sensitized Solar Cells

ACS Appl Mater Interfaces. 2017 Feb 15;9(6):5328-5336. doi: 10.1021/acsami.6b14649. Epub 2017 Jan 31.

Authors

Wenxiang Peng¹, Jun Du¹, Zhenxiao Pan¹, Naoki Nakazawa², Jiankun Sun³, Zhonglin Du¹, Gencai Shen¹, Juan Yu¹, Jin-Song Hu³, Qing Shen^{2

4}, Xinhua Zhong^{1

5}

Affiliations

¹ Key Laboratory for Advanced Materials, School of Chemistry and Molecular Engineering, East China University of Science and Technology , Shanghai 200237, China.
² Department of Engineering Science, University of Electro-Communications , Tokyo 182-8585, Japan.
³ Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
⁴ Japan Science and Technology Agency (JST) , Saitama 332-0012, Japan.
⁵ College of Materials and Energy, South China Agricultural University , 483 Wushan Road, Guangzhou 510642, China.

PMID: 28092935
DOI: 10.1021/acsami.6b14649

Abstract

I-III-VI₂ group "green" quantum dots (QDs) are attracting increasing attention in photoelectronic conversion applications. Herein, on the basis of the "simultaneous nucleation and growth" approach, Cu-In-Ga-Se (CIGSe) QDs with light harvesting range of about 1000 nm were synthesized and used as sensitizer to construct quantum dot sensitized solar cells (QDSCs). Inductively coupled plasma atomic emission spectrometry (ICP-AES), wild-angle X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses demonstrate that the Ga element was alloyed in the Cu-In-Se (CISe) host. Ultraviolet photoelectron spectroscopy (UPS) and femtosecond (fs) resolution transient absorption (TA) measurement results indicate that the alloying strategy could optimize the electronic structure in the obtained CIGSe QD material, thus matching well with TiO₂ substrate and favoring the photogenerated electron extraction. Open circuit voltage decay (OCVD) and impedance spectroscopy (IS) tests indicate that the intrinsic recombination in CIGSe QDSCs was well suppressed relative to that in CISe QDSCs. As a result, CIGSe based QDSCs with use of titanium mesh supported mesoporous carbon counter electrode exhibited a champion efficiency of 11.49% (J_sc = 25.01 mA/cm², V_oc = 0.740 V, FF = 0.621) under the irradiation of full one sun in comparison with 9.46% for CISe QDSCs.

Keywords: Cu−In−Ga−Se (CIGSe) QDs; alloying strategy; high efficiency; photovoltaic cells; quantum dot sensitized solar cells.