scholarly journals Carrier Formation Dynamics of Organic Photovoltaics as Investigated by Time-Resolved Spectroscopy

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Kouhei Yonezawa ◽  
Minato Ito ◽  
Hayato Kamioka ◽  
Takeshi Yasuda ◽  
Liyuan Han ◽  
...  

Bulk heterojunction (BHJ) based on a donor (D) polymer and an acceptor (A) fullerene derivative is a promising organic photovoltaics (OPV). In order to improve the incident photon-to-current efficiency (IPCE) of the BHJ solar cell, a comprehensive understanding of the ultrafast dynamics of excited species, such as singlet exciton (D*), interfacial charge-transfer (CT) state, and carrier (D+), is indispensable. Here, we performed femtosecond time-resolved spectroscopy of two prototypical BHJ blend films: poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend film and poly(9,9′-dioctylfluorene-co-bithiophene) (F8T2)/[6,6]-phenyl C71-butyric acid methyl ester (PC70BM) blend film. We decomposed differential absorption spectra into fast, slow, and constant components via two-exponential fitting at respective probe photon energies. The decomposition procedure clearly distinguished photoinduced absorptions (PIAs) due to D*, CT, and D+. Based on these assignments, we will compare the charge dynamics between the F8T2/PC70BM and P3HT/PCBM blend films.

2019 ◽  
Vol 116 (44) ◽  
pp. 22037-22043 ◽  
Author(s):  
Mohammad Mahdi Tavakoli ◽  
Riccardo Po ◽  
Gabriele Bianchi ◽  
Alessandra Cominetti ◽  
Chiara Carbonera ◽  
...  

Organic photovoltaics (OPVs) have attracted tremendous attention in the field of thin-film solar cells due to their wide range of applications, especially for semitransparent devices. Here, we synthesize a dithiaindacenone-thiophene-benzothiadiazole-thiophene alternating donor copolymer named poly{[2,7-(5,5-didecyl-5H-1,8-dithia-as-indacenone)]-alt-[5,5-(5′,6′-dioctyloxy-4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]} (PDTIDTBT), which shows a relatively wide bandgap of 1.82 eV, good mobility, and high transmittance and ambient stability. In this work, we fabricate an OPV device using monolayer graphene as top electrode. Due to the stability of PDTIDTBT in air and water, we use a wet transfer technique for graphene to fabricate semitransparent OPVs. We demonstrate OPVs based on the PDTIDTBT:Phenyl-C61/71-butyric acid methyl ester (PCBM) blend with maximum power conversion efficiencies (PCEs) of 6.1 and 4.75% using silver and graphene top electrodes, respectively. Our graphene-based device shows a high average visible transmittance (AVT) of 55%, indicating the potential of PDTIDTBT for window application and tandem devices. Therefore, we also demonstrate tandem devices using the PDTIDTBT:Phenyl-C61-butyric acid methyl ester (PC60BM) blend in both series and parallel connections with average PCEs of 7.3 and 7.95%, respectively. We also achieve a good average PCE of 8.26% with an average open circuit voltage (Voc) of 1.79 V for 2-terminal tandem OPVs using this blend. Based on tandem design, an OPV with PCE of 6.45% and AVT of 38% is demonstrated. Moreover, our devices show improved shelf life and ultraviolet (UV) stability (using CdSe/ZnS core shell quantum dots [QDs]) in ambient with 45% relative humidity.


2016 ◽  
Vol 4 (9) ◽  
pp. 3335-3341 ◽  
Author(s):  
Yufei Zhong ◽  
Kaori Suzuki ◽  
Daishi Inoue ◽  
Daisuke Hashizume ◽  
Seiichiro Izawa ◽  
...  

Nanorod-shaped crystals of PCBM grew in polymer blend films from the interface of pre-crystallized PCBM films.


ACS Nano ◽  
2011 ◽  
Vol 5 (4) ◽  
pp. 3132-3140 ◽  
Author(s):  
Andrew H. Rice ◽  
Rajiv Giridharagopal ◽  
Sam X. Zheng ◽  
Fumio S. Ohuchi ◽  
David S. Ginger ◽  
...  

2009 ◽  
pp. 10000 ◽  
Author(s):  
Jessica J. Benson-Smith ◽  
Hideo Ohkita ◽  
Steffan Cook ◽  
James R. Durrant ◽  
Donal D. C. Bradley ◽  
...  

Polymer ◽  
2013 ◽  
Vol 54 (2) ◽  
pp. 490-494 ◽  
Author(s):  
Bin Yang ◽  
Zhengguo Xiao ◽  
Yongbo Yuan ◽  
Tanjore V. Jayaraman ◽  
Jeffrey E. Shield ◽  
...  

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