Diketopyrrolopyrrole-based oligomer modified TiO2 nanorods for air-stable and all solution processed poly(3-hexylthiophene):TiO2 bulk heterojunction inverted solar cell
Journal
Journal of Materials Chemistry
Journal Volume
22
Journal Issue
21
Pages
10589-10596
Date Issued
2012
Author(s)
Liao, Hsueh-Chung
Lee, Chia-Hsin
Ho, Yi-Chen
Jao, Meng-Huan
Tsai, Chieh-Ming
Chuang, Chih-Min
Shyue, Jing-Jong
Abstract
Diketopyrrolopyrrole-based oligomer was synthesized and used to modified TiO 2 nanorods. The surface modified TiO 2 was employed in the fabrication of air-stable and all solution processed poly(3-hexylthiophene): titanium dioxide nanorods (P3HT:TiO 2 nanorods) bulk heterojunction (BHJ) inverted solar cells. The oligomer (copolymerized 4,5-diaza-9,9′- spirobifluorene with diketopyrrolopyrrole (PZFDPP)) was synthesized by Stille coupling reaction. The PZFDPP was coated on TiO 2 nanorods by refluxing the TiO 2 nanorods in oligomer containing solution at low temperature (70 °C). A concentration gradient profile of polymer/nanocrystals (P3HT/TiO 2 nanorods) BHJ was observed for the first time by X-ray photoelectron spectroscopy (XPS) technique together with in situ ion sputtering, showing that the TiO 2-rich region and P3HT rich region are aggregated adjacent to electron transport layer (ETL) and hole transport layer (HTL) respectively. The obtained depth profile indicates the inverted device structure is more suitable for polymer/inorganic nanocrystals BHJ solar cells. Furthermore, instead of using an energy consuming process for ETL layer deposition, the PZFDPP modified TiO 2 nanorods were used to deposit the ETL layer by spin coating. The surface features and properties of deposited TiO 2 ETL that was coated by PZFDPP were systematically investigated. The developed photovoltaic device shows a promising power conversion efficiency (PCE) of 1.2% benefited from improved electron mobility in P3HT:TiO 2 BHJ film and across the ETL/active layer interfaces. Moreover, the device is extremely stable stored in ambient condition without encapsulation (less than 10% loss over 1000 h test). The results of this work demonstrate the successful development of highly efficient and air-stable polymer/inorganic nanocrystal hybrid BHJ inverted solar cells based on chemically modified nanocrystals which significantly extend the current knowledge of device fabrication. © The Royal Society of Chemistry 2012.
SDGs
Other Subjects
Air-stable; Ambient conditions; Bulk heterojunction; Chemically modified; Concentration gradients; Depth profile; Device fabrications; Diketopyrrolopyrroles; Electron transport layers; Hole transport layers; In-situ; Inverted devices; Ion sputtering; Layer deposition; Layer interfaces; Low temperatures; Photovoltaic devices; Poly (3-hexylthiophene); Power conversion efficiencies; Refluxing; Solution-processed; Spirobifluorene; Stille coupling reaction; Surface feature; Surface-modified; TiO; Conversion efficiency; Electron mobility; Heterojunctions; Interfaces (materials); Nanocrystals; Nanorods; Oligomers; Photoelectrons; Polymers; X ray photoelectron spectroscopy; Titanium dioxide
Type
journal article
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