Solution-processed zinc oxide nanoparticles as interlayer materials for inverted organic solar cells

• Published in: Solar energy materials and solar cells Vol. 108; pp. 156 - 163
• Main Authors: Ibrahem, Mohammed Aziz, Wei, Hung-Yu, Tsai, Meng-Hung, Ho, Kuo-Chuan, Shyue, Jing-Jong, Chu, Chih Wie
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2013; Elsevier
• Subjects: Annealing; Applied sciences; Buffer layer; Devices; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Energy; Exact sciences and technology; Interlayers; Nanoparticles; Natural energy; Phase separation; Photoelectric conversion; Photovoltaic cells; Photovoltaic conversion; Polymer solar cells; Polystyrene resins; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Wet grinding; Zinc oxide; ZnO; Nanoparticles; Wet grinding; Buffer layer; ZnO; Polymer solar cells; Interfacial layer; Interlayers; Heat treatment; Fullerene compounds; Nanoparticle; Conversion rate; Machining; Annealing temperature; Amplitude modulation; Organic solar cells; Grinding; Optimization; Thiophene derivative polymer; Energy conversion; Illumination; Zinc oxide; Growth from solution; Low temperature; Heterojunction; Annealing; Polymer blends; Active layer; Solar cell; Air mass; Styrenesulfonic acid polymer; Styrenesulfonate polymer; Photoelectric current
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2012.09.007

This paper describes inverted bulk heterojunction organic solar cells featuring solution-processed zinc oxide nanoparticles (ZnO NPs) as an electron extraction layer, prepared at relatively low annealing temperatures (≤150°C). A solution of ZnO NPs (average size: 25nm) was prepared using a wet grinding method. When the ZnO interlayer was present in the solar cell, the vertical phase separation of the active layers prepared with and without solvent annealing exhibited similar gradient concentrations and, therefore, similar photocurrent generation, both of which were superior to those of conventional devices incorporating a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS) hole extraction layer. We attribute this vertical phase separation to the similar surface energies of the fullerene derivative and the ZnO interlayer. Under simulated air mass (AM) 1.5G illumination at 100mWcm−2, the power conversion efficiency of the optimized device was approximately 4%. [Display omitted] ► Simple and cheap method was demonstrated for the preparation of ZnO nanoparticle. ► Efficient inverted organic solar cells fabricated by utilizing the ZnO interlayer. ► Both solidification treatments of active layer given similar gradient concentration. ► Comparable power conversion energy achieved with and without solvent annealing.