Photovoltaic devices and characterization of a dodecyloxybenzothiadiazole- based copolymer

Purna P. Maharjan, Qiliang Chen, Lianjie Zhang, Olusegun Adebanjo, Nirmal Adhikari, Swaminathan Venkatesan, Prajwal Adhikary, Bjorn Vaagensmith, Qiquan Qiao

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27 Scopus citations


A conjugated copolymer based on alternating benzo[1,2-b;3,4-b′] dithiophene (BDT) donor and dodecyloxy substituted benzo[c][1,2,5]thiadiazole (ABT) acceptor units was prepared for application in organic solar cells. A power conversion efficiency (PCE) of ∼3% with a short-circuit current (Jsc) of 7.63 mA cm-2, an open-circuit voltage (V oc) of 0.71 V and a fill-factor (FF) of 53.74% was obtained under the illumination of AM 1.5 solar irradiation (100 mW cm-2). Photovoltaic devices and their transient properties with a blend of the copolymer and the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) at different ratios were studied using transient photovoltage (TPV), transient photocurrent (TPC) and atomic force microscopy (AFM) measurements. From the TPV and TPC measurements, the charge recombination times (τn) were found to be 21.1 μs, 12.6 μs and 10.5 μs, and the charge transport times (τd) were 1316 ns, 422 ns and 707 ns for the 1 : 0.5, 1 : 1 and 1 : 2 donor/acceptor (D/A) ratios, respectively. The 1 : 1 D/A ratio showed the shortest charge transport time (τd) and the longest charge diffusion length (Ln) according to, leading to the highest device performance among the three ratios.

Original languageEnglish (US)
Pages (from-to)6856-6863
Number of pages8
JournalPhysical Chemistry Chemical Physics
Issue number18
StatePublished - May 14 2013
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


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