Structural, optical, and hole transport properties of earth-abundant chalcopyrite (CuFeS2) nanocrystals

• Published in: MRS communications Vol. 8; no. 3; pp. 970 - 978
• Main Authors: Bastola, Ebin, Bhandari, Khagendra P., Subedi, Indra, Podraza, Nikolas J., Ellingson, Randy J.
• Format: Journal Article
• Language: English
• Published: New York, USA Cambridge University Press 01.09.2018; Springer International Publishing
• Subjects: Biomaterials; Cadmium telluride; Cadmium tellurides; Chalcopyrite; Characterization and Evaluation of Materials; Copper; Crystal growth; Crystal structure; Intermetallic compounds; Materials Engineering; Materials Science; Nanocrystals; Nanotechnology; Optical properties; Photovoltaic cells; Polymer Sciences; Research Letter; Research Letters; Solar cells; Spectroellipsometry; Spectrum analysis; Tellurides; Ternary systems; Thin films; Transport properties
• ISSN: 2159-6859; 2159-6867
• DOI: 10.1557/mrc.2018.117

Here, we report thiol-free thermal-injection synthesis of chalcopyrite (CuFeS2) nanocrystals (NCs) using iron (II) bromide (FeBr2), copper (II) acetaylacetonate (Cu(acac)2), and elemental sulfur (S). Controlled reaction temperature and growth time yield stable and phase-pure ternary CuFeS2 NCs exhibiting tetragonal crystal structure. With increasing growth time from 1 to 30 min, absorption peak slightly red shifts from 465 to 490 nm. Based on spectroscopic ellipsometry analysis, three electronic transitions at 0.652, 1.54, and 2.29 eV were found for CuFeS2 NC film. Also, CuFeS2 NC thin films are incorporated as hole transport layers in cadmium telluride solar cells reaching an efficiency of ~12%.