Chloride Passivation of ZnO Electrodes Improves Charge Extraction in Colloidal Quantum Dot Photovoltaics. Issue 33 (3rd July 2017)

• Record Type: Journal Article
• Authors: Choi, Jongmin; Kim, Younghoon; Jo, Jea Woong; Kim, Junghwan; Sun, Bin; Walters, Grant; García de Arquer, F. Pelayo; Quintero‐Bermudez, Rafael; Li, Yiying; Tan, Chih Shan; Quan, Li Na; Kam, Andrew Pak Tao; Hoogland, Sjoerd; Lu, Zhenghong; Voznyy, Oleksandr; Sargent, Edward H.
• Is Part Of: Advanced materials. Volume 29:Issue 33(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-07-03
• Subjects: band alignment -- passivation -- quantum‐dot solar cells -- ZnO; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201702350
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract : The tunable bandgap of colloidal quantum dots (CQDs) makes them an attractive material for photovoltaics (PV). The best present‐day CQD PV devices employ zinc oxide (ZnO) as an electron transport layer; however, it is found herein that ZnO's surface defect sites and unfavorable electrical band alignment prevent devices from realizing their full potential. Here, chloride (Cl)‐passivated ZnO generated from a solution of presynthesized ZnO nanoparticles treated using an organic‐solvent‐soluble Cl salt is reported. These new ZnO electrodes exhibit decreased surface trap densities and a favorable electronic band alignment, improving charge extraction from the CQD layer and achieving the best‐cell power conversion efficiency (PCE) of 11.6% and an average PCE of 11.4 ± 0.2%. Abstract : Surface‐defect‐passivated zinc oxide (ZnO) nanoparticles are achieved by a chloride (Cl)‐passivation process, exhibiting decreased surface trap density and favorable band alignment, improving electron extraction. With these benefits, a colloidal quantum dot (CQD) photovoltaic device prepared using Cl‐passivated ZnO shows a power conversion efficiency of 11.6%.