Absorption Spectrum‐Compensating Configuration Reduces the Energy Loss of Nonfullerene Organic Solar Cells. (11th November 2021)

• Record Type: Journal Article
• Authors: Ren, Hao; Ma, Yunlong; Liu, Hui‐Min; Chen, Jing‐De; Zhang, Ye‐Fan; Hou, Hong‐Yi; Li, Yan‐Qing; Zheng, Qingdong; Tang, Jian‐Xin
• Is Part Of: Advanced functional materials. Volume 32:Number 8(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-11-11
• Subjects: blazed grating -- light deflection -- metallic meta‐surfaces -- nonfullerene organic solar cells -- waveguide modes; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202109735
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Using narrow bandgap nonfullerene acceptors (NFAs) can broaden the absorption spectrum of organic solar cells (OSCs) to the near‐infrared region. However, the simultaneously decreased extinction coefficient of the active layer at the blue region results in inevitable light escaping and energy loss. Herein, a blazed grating‐based device configuration consisting of a patterned rear electrode is employed to compensate for the low absorption of nonfullerene OSCs. Experimental results reveal that the normal incidence light, especially blue light, that bounces off the patterned rear electrode is concentrated in a large tilted angle and subsequently trapped in waveguide mode. Along with the excitation of surface plasmon polariton, the structured nonfullerene OSCs using a new‐designed PM6:M36 active layer obtain the broadband absorption enhancement with 1.5 times increase at the blue region. The optimized device achieves an 8.95% increase in photocurrent and a champion power conversion efficiency of approaching 18%, which is the highest reported value among all the devices based on A‐D‐A type NFAs. Abstract : An effective light‐deflecting pattern is introduced to nonfullerene organic solar cells to improve energy conversion efficiency in the blue region. The normal incidence light is guided into a cavity‐like chamber and mostly captured by the active layer, resulting in broadband absorption enhancement. The optimized device based on all A‐D‐A type nonfullerene acceptors achieves the highest reported efficiency of approaching 18%.