The effect of interchain coupling on the reverse polarization of a high-energy exciton in conjugated polymers

2014 ◽  
Vol 378 (22-23) ◽  
pp. 1657-1661 ◽  
Author(s):  
Xiao-xue Li
Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 393
Author(s):  
Ja Eun Lee ◽  
Yoon Kim ◽  
Yang Ho Na ◽  
Nam Seob Baek ◽  
Jae Woong Jung ◽  
...  

We synthesized medium-band-gap donor-acceptor (D-A) -type conjugated polymers (PBTZCZ-L and PBTZCZ-H) consisting of a benzotriazole building block as an acceptor and a carbazole unit as a donor. In comparison with the polymers, a small conjugated molecule (BTZCZ-2) was developed, and its structural, thermal, optical, and photovoltaic properties were investigated. The power conversion efficiency (PCE) of the BTZCZ-2-based solar cell devices was less than 0.5%, considerably lower than those of polymer-based devices with conventional device structures. However, inverted solar cell devices configured with glass/ITO/ZnO:PEIE/BTZCZ-2:PC71BM/MoO3/Ag showed a tremendously improved efficiency (PCE: 5.05%, Jsc: 9.95 mA/cm2, Voc: 0.89 V, and FF: 57.0%). We believe that this is attributed to high energy transfer and excellent film morphologies.


Author(s):  
Rodrigo Elizalde-Segovia ◽  
Pratyusha Das ◽  
Billal Zayat ◽  
AHAMED IRSHAD ◽  
Barry Thompson ◽  
...  

Author(s):  
Yaxin Zhai ◽  
Chuanxiang Sheng ◽  
Z. Valy Vardeny

We used steady-state photoinduced absorption (PA), excitation dependence (EXPA( ω )) spectrum of the triplet exciton PA band, and its magneto-PA (MPA( B )) response to investigate singlet fission (SF) of hot excitons into two separated triplet excitons, in two luminescent and non-luminescent π -conjugated polymers. From the high energy step in the triplet EXPA( ω ) spectrum of the luminescent polymer poly(dioctyloxy)phenylenevinylene (DOO-PPV) films, we identified a hot-exciton SF (HE-SF) process having threshold energy at E ≈2 E T (=2.8 eV, where E T is the energy of the lowest lying triplet exciton), which is about 0.8 eV above the lowest singlet exciton energy. The HE-SF process was confirmed by the triplet MPA( B ) response for excitation at E >2 E T , which shows typical SF response. This process is missing in DOO-PPV solution, showing that it is predominantly interchain in nature. By contrast, the triplet EXPA( ω ) spectrum in the non-luminescent polymer polydiacetylene (PDA) is flat with an onset at E = E g (≈2.25 eV). From this, we infer that intrachain SF that involves a triplet–triplet pair state, also known as the ‘dark’ 2A g exciton, dominates the triplet photogeneration in PDA polymer as E g >2 E T . The intrachain SF process was also identified from the MPA( B ) response of the triplet PA band in PDA. Our work shows that the SF process in π -conjugated polymers is a much more general process than thought previously.


1997 ◽  
Vol 56 (20) ◽  
pp. 13162-13166 ◽  
Author(s):  
Shi-jie Xie ◽  
Jian-Hua Wei ◽  
De-Sheng Liu ◽  
Liang-Mo Mei ◽  
D. L. Lin

2005 ◽  
Vol 44 (7B) ◽  
pp. 5839-5842 ◽  
Author(s):  
Satoshi Tsukuda ◽  
Shu Seki ◽  
Masaki Sugimoto ◽  
Seiichi Tagawa

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