Title: Optoelectronic Properties of Strontium and Barium Copper Sulfides Prepared by Combinatorial Sputtering

Abstract

Optically transparent materials with p-type electrical conductivity can facilitate the development of transparent electronics and improve the efficiency of photovoltaic solar cells. Sulfide materials represent an interesting alternative to oxides for these applications due to better hole transport properties. We prepare transparent and conductive Ba-Cu-S thin films by combinatorial cosputtering and characterized for their composition, structure, and optoelectronic properties. The conductivity and transparency of these films are found to be strongly dependent on their chemical composition and the substrate temperature during growth. The conductivity of BaCu₂S₂ and BaCu₄S₃ can reach 53 S/cm (at 250 °C) and 74 S/cm (at 200 degrees C), respectively, which is higher than their solution processed/bulk counterparts. The 90% reflectance corrected transmittance is achieved in the wavelength range 600-1000 nm for BaCu₂S₂ and 650-1000 nm for BaCu₄S₃ (at 250 °C). These electrical and optical properties are comparable with other recently presented transparent p-type conductors, while the 200-350 degrees C processing temperature is low enough to be used in semiconductor devices with limited thermal budgets. Some attempts have been made to synthesize the related Sr-Cu-S materials, following the theoretical suggestion of their potential as transparent p-type conductors, but these attempts resulted only in phase-separated SrS and CuxSmore » phases. Alloying BaCu₂S₂ with Sr on the Ba site on the other hand increases the conductivity to >100 S/cm while only slightly compromising the transparency of the material. To explain the difference between the Ba and the Sr containing copper sulfides, the lower bounds on the SrCu₂S₂ and SrCu₄S₃ formation enthalpies are estimated. While the doping of the Ba-Cu-S materials presented here is too large for application in transparent electronics, it is promising for potential use as p-type contact layers in thin film solar cells.« less

Authors:

Han, Yanbing  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-1159-1005"

Siol, Sebastian  ^[2];

• Search DOE PAGES for author "Siol, Sebastian"
• Search DOE PAGES for ORCID "0000-0002-0907-6525"

Zhang, Qun ^[3]; Zakutayev, Andriy  ^[2]

• Search DOE PAGES for author "Zakutayev, Andriy"
• Search DOE PAGES for ORCID "0000-0002-3054-5525"

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+ Show Author Affiliations

1. Fudan Univ., Shanghai (China). Dept. of Materials Science; National Renewable Energy Lab. (NREL), Golden, CO (United States)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
3. Fudan Univ., Shanghai (China). Dept. of Materials Science

Publication Date:

Wed Sep 27 00:00:00 EDT 2017

Research Org.:

National Renewable Energy Lab. (NREL), Golden, CO (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Next Generation of Materials by Design: Incorporating Metastability (CNGMD)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office

OSTI Identifier:

1399355

Report Number(s):

NREL/JA-5K00-70119
Journal ID: ISSN 0897-4756

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Chemistry of Materials

Additional Journal Information:

Journal Volume: 29; Journal Issue: 19; Journal ID: ISSN 0897-4756

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

14 SOLAR ENERGY; 36 MATERIALS SCIENCE; photovoltaics; transparent electronics; optoelectronic properties