Anoop C Sathyadevan Nair, Anju Rajan, K P Adarsh Raj, Abhishek Melarkode Rajendran, Megha Raichal Benny, Kavya Murali, Pattiyil Parameswaran, C S Suchand Sangeeth, Raghu Chatanathodi, Vari Sivaji Reddy
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引用次数: 0
Abstract
Zinc oxide (ZnO) is widely used as a cathode buffer layer (CBL) in inverted organic solar cells (OSCs). Performance enhancement of OSCs by work function (WF) reduction of the ZnO CBL is a prominent area of research. Here, we report the role of three phenanthroline ligands, 1,10-phenanthroline (Phen-A), 4,7-phenanthroline (Phen-B), and 1,7-phenanthroline (Phen-C), in reducing the WF of ZnO. Phen-A functionalized ZnO has the lowest WF, which can be attributed to the effective donation of nitrogen lone pairs to the Zn center thereby effectively raising the Fermi energy of the system. Significant improvements in efficiency and stability have been experimentally demonstrated by using functionalized ZnO thin films as the CBLs in PTB7:PC70BM-based OSCs. The X-ray photoelectron spectroscopy analysis revealed the formation of a Zn–N bond and a significant reduction in oxygen deficiency defects due to the functionalization of the ZnO surface with phenanthroline ligands. The density functional theory results confirmed the formation of strong N–Zn bonding with adsorption energies −2.05, −1.77, and −1.33 eV for Phen-A, Phen-B, and Phen-C, respectively. The improved interfacial properties due to functionalization of the ZnO surface resulted in 13.2, 7.8, and 6.7% enhancement in power conversion efficiency for Phen-A, Phen-B, and Phen-C, respectively.
期刊介绍:
ACS Applied Energy Materials is an interdisciplinary journal publishing original research covering all aspects of materials, engineering, chemistry, physics and biology relevant to energy conversion and storage. The journal is devoted to reports of new and original experimental and theoretical research of an applied nature that integrate knowledge in the areas of materials, engineering, physics, bioscience, and chemistry into important energy applications.