Post-annealing to recover the reduced open-circuit voltage caused by solvent annealing in organic solar cells. Issue 16 (8th April 2016)

• Record Type: Journal Article
• Authors: Xie, Yuanpeng; Zhou, Weihua; Yin, Jingping; Hu, Xiaotian; Zhang, Lin; Meng, Xiangchuan; Ai, Qingyun; Chen, Yiwang
• Is Part Of: Journal of materials chemistry. Volume 4:Issue 16(2016)
• Page Start: 6158
• Page End: 6166
• Publication Date: 2016-04-08
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c6ta00835f
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The tremendous loss in open-circuit voltage ( V oc ) upon solvent annealing in p -DTS(FBTTh2 )2 :PC71 BM could be recovered by subsequent post-thermal annealing. Abstract : The tremendous loss of 246 mV in open-circuit voltage ( V oc ) upon solvent annealing in p -DTS(FBTTh2 )2 :PC71 BM solar cells that has been observed could be recovered by post-annealing. Following solvent annealing, subsequent thermal annealing of the active layer could not achieve full recovery of V oc, which is attributed to minor variation in morphology, crystalline behavior and absorption edge. However, after completing fabrication of the entire device, subsequent post-annealing succeeded in recovery of V oc to 225 mV on average. Through analysis of photocurrent density ( J ph ) versus the effective voltage ( V eff ) and short-circuit current ( J sc ) versus light intensity, it is shown that the charge collection ability increased and bimolecular recombination decreased in the device after post-annealing. Based on dark J – V characteristics and fitting curves, the reverse saturation current ( J 0 ) value reduced to as low as 6.85 × 10 −11 A cm −2, demonstrating that the method of post-annealing has an advantage over thermal annealing, as it leads to better interfacial contact between active layer and back electrode.