A Tandem Organic Solar Cell with PCE of 14.52% Employing Subcells with the Same Polymer Donor and Two Absorption Complementary Acceptors

• Published in: Advanced materials (Weinheim) 2019-05, Vol.31 (18), p.e1804723-n/a
• Main Authors: Meng, Lingxian, Yi, Yuan‐Qiu‐Qiang, Wan, Xiangjian, Zhang, Yamin, Ke, Xin, Kan, Bin, Wang, Yanbo, Xia, Ruoxi, Yip, Hin‐Lap, Li, Chenxi, Chen, Yongsheng
• Format: Article
• Language: English
• Subjects: Absorption; Benzothiophene; Energy conversion efficiency; Materials science; nonfullerene acceptors; Organic chemistry; organic solar cells; Photovoltaic cells; Solar cells; tandem devices; Thermalization (energy absorption)
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201804723

The tandem structure is an efficient way to simultaneously tackle absorption and thermalization losses of the single junction solar cells. In this work, a high‐performance tandem organic solar cell (OSC) using two subcells with the same donor poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione))] (PBDB‐T) and two acceptors, F‐M and 2,9‐bis(2‐methylene‐(3(1,1‐dicyanomethylene)benz[f ]indanone))7,12‐dihydro‐(4,4,10,10‐tetrakis(4‐hexylphenyl)‐5,11‐diocthylthieno[3′,2′:4,5]cyclopenta[1,2‐b]thieno[2″,3″:3′,4′]cyclopenta[1′,2′:4,5]thieno[2,3‐f][1]benzothiophene (NNBDT), with complementary absorptions is demonstrated. The two subcells show high Voc with value of 0.99 V for the front cell and 0.86 V for the rear cell, which is the prerequisite for obtaining high Voc of their series‐connected tandem device. Although there is much absorption overlap for the subcells, a decent Jsc of the tandem cell is still obtained owing to the complementary absorption of the two acceptors in a wide range. With systematic device optimizations, a best power conversion efficiency of 14.52% is achieved for the tandem device, with a high Voc of 1.82 V, a notable FF of 74.7%, and a decent Jsc of 10.68 mA cm−2. This work demonstrates a promising strategy of fabricating high‐efficiency tandem OSCs through elaborate selection of the active layer materials in each subcell and tradeoff of the Voc and Jsc of the tandem cells. A tandem organic solar cell is fabricated employing subcells with the same donor PBDB‐T and two acceptors F‐M and NNBDT with complementary absorptions. A power conversion efficiency of 14.52% is achieved with a high Voc of 1.82 V, a notable FF of 74.7%, and a decent Jsc of 10.68 mA cm−2.