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Title: Ferroelectric field effect of the bulk heterojunction in polymer solar cells

Abstract

A ferroelectric field effect in the bulk heterojunction was found when an external electric field (EEF) was applied on the active layer of polymer solar cells (PSCs) during the annealing process of the active layer spin-coated with poly(3-hexylthiophene):[6,6]-phenyl-C{sub 61} butyric acid methyl ester. For one direction field, the short circuit current density of PSCs was improved from 7.2 to 8.0 mA/cm{sup 2}, the power conversion efficiency increased from 2.4% to 2.8%, and the incident photon-to-current conversion efficiency increased from 42% to 49% corresponding to the different EEF magnitude. For an opposite direction field, the applied EEF brought a minus effect on the performance mentioned above. EEF treatment can orientate molecular ordering of the polymer, and change the morphology of the active layer. The authors suggest a explanation that the ferroelectric field has been built in the active layer, and therefore it plays a key role in PSCs system. A needle-like surface morphology of the active film was also discussed.

Authors:
; ; ;  [1];  [2]; ;  [1]
  1. College of Physics and Electronic Engineering, Henan Normal University, Xinxiang 453007 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22303881
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 25; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; CONVERSION; CURRENT DENSITY; CURRENTS; EFFICIENCY; ELECTRIC FIELDS; ELECTRICAL FAULTS; FERROELECTRIC MATERIALS; FILMS; HETEROJUNCTIONS; PHOTONS; POLYMERS; SOLAR CELLS; SPIN; SURFACES

Citation Formats

Li, Meng, Ma, Heng, E-mail: hengma@henannu.edu.cn, Liu, Hairui, Jiang, Yurong, Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007, Niu, Heying, and Amat, Adil. Ferroelectric field effect of the bulk heterojunction in polymer solar cells. United States: N. p., 2014. Web. doi:10.1063/1.4885216.
Li, Meng, Ma, Heng, E-mail: hengma@henannu.edu.cn, Liu, Hairui, Jiang, Yurong, Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007, Niu, Heying, & Amat, Adil. Ferroelectric field effect of the bulk heterojunction in polymer solar cells. United States. doi:10.1063/1.4885216.
Li, Meng, Ma, Heng, E-mail: hengma@henannu.edu.cn, Liu, Hairui, Jiang, Yurong, Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007, Niu, Heying, and Amat, Adil. Mon . "Ferroelectric field effect of the bulk heterojunction in polymer solar cells". United States. doi:10.1063/1.4885216.
@article{osti_22303881,
title = {Ferroelectric field effect of the bulk heterojunction in polymer solar cells},
author = {Li, Meng and Ma, Heng, E-mail: hengma@henannu.edu.cn and Liu, Hairui and Jiang, Yurong and Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007 and Niu, Heying and Amat, Adil},
abstractNote = {A ferroelectric field effect in the bulk heterojunction was found when an external electric field (EEF) was applied on the active layer of polymer solar cells (PSCs) during the annealing process of the active layer spin-coated with poly(3-hexylthiophene):[6,6]-phenyl-C{sub 61} butyric acid methyl ester. For one direction field, the short circuit current density of PSCs was improved from 7.2 to 8.0 mA/cm{sup 2}, the power conversion efficiency increased from 2.4% to 2.8%, and the incident photon-to-current conversion efficiency increased from 42% to 49% corresponding to the different EEF magnitude. For an opposite direction field, the applied EEF brought a minus effect on the performance mentioned above. EEF treatment can orientate molecular ordering of the polymer, and change the morphology of the active layer. The authors suggest a explanation that the ferroelectric field has been built in the active layer, and therefore it plays a key role in PSCs system. A needle-like surface morphology of the active film was also discussed.},
doi = {10.1063/1.4885216},
journal = {Applied Physics Letters},
number = 25,
volume = 104,
place = {United States},
year = {Mon Jun 23 00:00:00 EDT 2014},
month = {Mon Jun 23 00:00:00 EDT 2014}
}
  • The price of energy to separate tightly bound electron-hole pair (or charge-transfer state) and extract freely movable charges from low-mobility materials represents fundamental losses for many low-cost photovoltaic devices. In bulk heterojunction (BHJ) polymer solar cells (PSCs), approximately 50% of the total efficiency lost among all energy loss pathways is due to the photogenerated charge carrier recombination within PSCs and low charge carrier mobility of disordered organic materials. To address these issues, we introduce magnetic nanoparticles (MNPs) and orientate these MNPS within BHJ composite by an external magnetostatic field. Over 50% enhanced efficiency was observed from BHJ PSCs incorporated withmore » MNPs and an external magnetostatic field alignment when compared to the control BHJ PSCs. The optimization of BHJ thin film morphology, suppression of charge carrier recombination, and enhancement in charge carrier collection result in a greatly increased short-circuit current density and fill factor, as a result, enhanced power conversion efficiency.« less
  • Device performances of BHJ solar cells based on poly[(4,4-didodecyldithieno[3,2-b:2’,3’-d]silole)-2,6-diyl-alt-(2,1,3-benzoxadiazole)-4,7-diyl]and PC₇₁BM improve by capping the chain ends with thiophene fragments. This structural modification yields materials that are more thermally robust and that can be used in devices with thicker films – important considerations for enabling the mass production of plastic solar cells.
  • We report the synthesis and characterization of a series of five extended arylacetylenes, 9,10-bis-{[m,p-bis(hexyloxy)phenyl]ethynyl}-anthracene (A-P6t, 1), 9,10-bis-[(p-{[m,p-bis(hexyloxy) phenyl]ethynyl}phenyl)ethynyl]-anthracene (PA-P6t, 2), 4,7-bis-{[m,p-bis(hexyloxy)phenyl]ethynyl}-2,1,3-benzothiadiazole (BTZ-P6t, 5), 4,7-bis(5-{[m,p-bis(hexyloxy)phenyl]ethynyl}thien-2-yl)-2,1,3-benzothiadiazole (TBTZ-P6t, 6), and 7,7'-({[m,p-bis(hexyloxy)phenyl]ethynyl}-2,1,3-benzothiadiazol-4,4'-ethynyl)-2,5-thiophene (BTZT-P6t, 7), and two arylvinylenes, 9,10-bis-{(E)-[m,p-bis(hexyloxy)phenyl]vinyl}-anthracene (A-P6d, 3), 9,10-bis-[(E)-(p-{(E)-[m,p-bis(hexyloxy)phenyl]vinyl}phenyl)vinyl]-anthracene (PA-P6d, 4). Trends in optical absorption spectra and electrochemical redox processes are first described. Next, the thin-film microstructures and morphologies of films deposited from solution under various conditions are investigated, and organic field-effect transistors (OFETs) and bulk heterojunction photovoltaic (OPV) cells fabricated. We find that substituting acetylenic for olefinic linkers on the molecular cores significantly enhances device performance. OFET measurements reveal that allmore » seven of the semiconductors are FET-active and, depending on the backbone architecture, the arylacetylenes exhibit good p-type mobilities (μ up to ~0.1 cm 2 V -1 s -1) when optimum film microstructural order is achieved. OPV cells using [6,6]-phenyl C 61-butyric acid methyl ester (PCBM) as the electron acceptor exhibit power conversion efficiencies (PCEs) up to 1.3% under a simulated AM 1.5 solar irradiation of 100 mW/cm 2. These results demonstrate that arylacetylenes are promising hole-transport materials for p-channel OFETs and promising donors for organic solar cells applications. A direct correlation between OFET arylacetylene hole mobility and OPV performance is identified and analyzed.« less