skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: High open-circuit voltage small-molecule p-DTS(FBTTh 2 )2.ICBA bulk heterojunction solar cells – morphology, excited-state dynamics, and photovoltaic performance

Abstract

The photovoltaic performance of bulk heterojunction solar cells using the solution-processable small molecule donor 7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophene]-5-yl)benzo[c][1,2,5]thiadiazole) (p-DTS(FBTTh2)2 in combination with indene-C60 bis-adduct (ICBA) as an acceptor is systematically optimized by altering the processing conditions. A high open-circuit voltage of 1 V, more than 0.2 V higher than that of a p-DTS(FBTTh2)2:PC70BM blend, is achieved. However, the power conversion efficiency remains around 5% and thus is lower than ~8% previously reported for p-DTS(FBTTh2)2:PC70BM. Transient absorption (TA) pump–probe spectroscopy over a wide spectral (Vis-NIR) and dynamic (fs to μs) range in combination with multivariate curve resolution analysis of the TA data reveals that generation of free charges is more efficient in the blend with PC70BM as an acceptor. In contrast, blends with ICBA create more coulombically bound interfacial charge transfer (CT) states, which recombine on the sub-nanosecond timescale by geminate recombination. Furthermore, the ns to μs charge carrier dynamics in p-DTS(FBTTh2)2:ICBA blends are only weakly intensity dependent implying a significant contribution of recombination from long-lived CT states and trapped charges, while those in p-DTS(FBTTh2)2:PC70BM decay via an intensity-dependent recombination mechanism indicating that spatially separated (free) charge carriers are observed, which can be extracted as photocurrent from the device.

Authors:
 [1];  [2];  [1];  [3];  [3];  [4];  [3]
  1. Agency for Science Technology and Research (A*STAR) (Singapore). Inst. of Materials Research and Engineering (IMRE).
  2. Max Planck Inst. for Polymer Research, Mainz (Germany)
  3. Univ. of California at Santa Barbara, Santa Barbara, CA (United States). Center for Polymers and Organic Solids.
  4. Max Planck Inst. for Polymer Research, Mainz (Germany)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1215416
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Materials Chemistry. A
Additional Journal Information:
Journal Volume: 3; Journal Issue: 4; Journal ID: ISSN 2050-7488
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY

Citation Formats

Ko Kyaw, Aung Ko, Gehrig, Dominik, Zhang, Jie, Huang, Ye, Bazan, Guillermo C., Laquai, Frédéric, and Nguyen, Thuc -Quyen. High open-circuit voltage small-molecule p-DTS(FBTTh 2 )2.ICBA bulk heterojunction solar cells – morphology, excited-state dynamics, and photovoltaic performance. United States: N. p., 2014. Web. doi:10.1039/C4TA06256F.
Ko Kyaw, Aung Ko, Gehrig, Dominik, Zhang, Jie, Huang, Ye, Bazan, Guillermo C., Laquai, Frédéric, & Nguyen, Thuc -Quyen. High open-circuit voltage small-molecule p-DTS(FBTTh 2 )2.ICBA bulk heterojunction solar cells – morphology, excited-state dynamics, and photovoltaic performance. United States. https://doi.org/10.1039/C4TA06256F
Ko Kyaw, Aung Ko, Gehrig, Dominik, Zhang, Jie, Huang, Ye, Bazan, Guillermo C., Laquai, Frédéric, and Nguyen, Thuc -Quyen. 2014. "High open-circuit voltage small-molecule p-DTS(FBTTh 2 )2.ICBA bulk heterojunction solar cells – morphology, excited-state dynamics, and photovoltaic performance". United States. https://doi.org/10.1039/C4TA06256F. https://www.osti.gov/servlets/purl/1215416.
@article{osti_1215416,
title = {High open-circuit voltage small-molecule p-DTS(FBTTh 2 )2.ICBA bulk heterojunction solar cells – morphology, excited-state dynamics, and photovoltaic performance},
author = {Ko Kyaw, Aung Ko and Gehrig, Dominik and Zhang, Jie and Huang, Ye and Bazan, Guillermo C. and Laquai, Frédéric and Nguyen, Thuc -Quyen},
abstractNote = {The photovoltaic performance of bulk heterojunction solar cells using the solution-processable small molecule donor 7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophene]-5-yl)benzo[c][1,2,5]thiadiazole) (p-DTS(FBTTh2)2 in combination with indene-C60 bis-adduct (ICBA) as an acceptor is systematically optimized by altering the processing conditions. A high open-circuit voltage of 1 V, more than 0.2 V higher than that of a p-DTS(FBTTh2)2:PC70BM blend, is achieved. However, the power conversion efficiency remains around 5% and thus is lower than ~8% previously reported for p-DTS(FBTTh2)2:PC70BM. Transient absorption (TA) pump–probe spectroscopy over a wide spectral (Vis-NIR) and dynamic (fs to μs) range in combination with multivariate curve resolution analysis of the TA data reveals that generation of free charges is more efficient in the blend with PC70BM as an acceptor. In contrast, blends with ICBA create more coulombically bound interfacial charge transfer (CT) states, which recombine on the sub-nanosecond timescale by geminate recombination. Furthermore, the ns to μs charge carrier dynamics in p-DTS(FBTTh2)2:ICBA blends are only weakly intensity dependent implying a significant contribution of recombination from long-lived CT states and trapped charges, while those in p-DTS(FBTTh2)2:PC70BM decay via an intensity-dependent recombination mechanism indicating that spatially separated (free) charge carriers are observed, which can be extracted as photocurrent from the device.},
doi = {10.1039/C4TA06256F},
url = {https://www.osti.gov/biblio/1215416}, journal = {Journal of Materials Chemistry. A},
issn = {2050-7488},
number = 4,
volume = 3,
place = {United States},
year = {Thu Nov 27 00:00:00 EST 2014},
month = {Thu Nov 27 00:00:00 EST 2014}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 28 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Artificial Photosynthesis: Solar Splitting of Water to Hydrogen and Oxygen
journal, March 1995


Triple Junction Polymer Solar Cells for Photoelectrochemical Water Splitting
journal, April 2013


Solar Water Splitting Cells
journal, November 2010


Solar Energy Supply and Storage for the Legacy and Nonlegacy Worlds
journal, November 2010


Carrier tunneling and device characteristics in polymer light‐emitting diodes
journal, February 1994


Cathode dependence of the open-circuit voltage of polymer:fullerene bulk heterojunction solar cells
journal, November 2003


Origin of the Open Circuit Voltage of Plastic Solar Cells
journal, October 2001


Efficient inverted polymer solar cells
journal, June 2006


Enhancement in open circuit voltage induced by deep interface hole traps in polymer-fullerene bulk heterojunction solar cells
journal, March 2009


On the origin of the open-circuit voltage of polymer–fullerene solar cells
journal, October 2009


Open circuit voltage enhancement due to reduced dark current in small molecule photovoltaic cells
journal, January 2009


Design Rules for Donors in Bulk-Heterojunction Solar Cells—Towards 10 % Energy-Conversion Efficiency
journal, March 2006


“Solvent Annealing” Effect in Polymer Solar Cells Based on Poly(3-hexylthiophene) and Methanofullerenes
journal, July 2007


Bulk heterojunction solar cells with internal quantum efficiency approaching 100%
journal, April 2009


An Easily Synthesized Blue Polymer for High-Performance Polymer Solar Cells
journal, September 2010


Indene−C60 Bisadduct: A New Acceptor for High-Performance Polymer Solar Cells
journal, February 2010


Combination of Indene-C 60 Bis-Adduct and Cross-Linked Fullerene Interlayer Leading to Highly Efficient Inverted Polymer Solar Cells
journal, December 2010


Efficient Polymer Solar Cells Based on Poly(3-hexylthiophene):Indene-C70 Bisadduct with a MoO3 Buffer Layer
journal, December 2011


Dynamics of exciton dissociation in donor-acceptor polymer heterojunctions
journal, April 2013


Coulomb Barrier for Charge Separation at an Organic Semiconductor Interface
journal, November 2008


Charge-Transfer Excitons at Organic Semiconductor Surfaces and Interfaces
journal, November 2009


The role of spin in the kinetic control of recombination in organic photovoltaics
journal, August 2013


Bulk Heterojunction Solar Cells with Large Open-Circuit Voltage: Electron Transfer with Small Donor-Acceptor Energy Offset
journal, March 2011


Novel high performance asymmetrical squaraines for small molecule organic solar cells with a high open circuit voltage of 1.12 V
journal, January 2013


Efficient Polymer Solar Cells with a High Open Circuit Voltage of 1 Volt
journal, September 2012


Non-Basic High-Performance Molecules for Solution-Processed Organic Solar Cells
journal, June 2012


Device annealing effect in organic solar cells with blends of regioregular poly(3-hexylthiophene) and soluble fullerene
journal, February 2005


Investigation of annealing effects and film thickness dependence of polymer solar cells based on poly(3-hexylthiophene)
journal, August 2005


Morphology-Dependent Trap Formation in High Performance Polymer Bulk Heterojunction Solar Cells
journal, June 2011


Nanoscale Phase Separation and High Photovoltaic Efficiency in Solution-Processed, Small-Molecule Bulk Heterojunction Solar Cells
journal, October 2009


Ultrafast Long-Range Charge Separation in Organic Semiconductor Photovoltaic Diodes
journal, December 2013


Transient Absorption data Analysis by Soft-Modelling
conference, April 2014

  • Howard, I. A.; Mangold, H.; Etzold, F.
  • Selected Lectures Presented at Symposium on Ultrafast Dynamics of the 7th International Conference on Materials for Advanced Technologies, Ultrafast Dynamics in Molecules, Nanostructures and Interfaces
  • https://doi.org/10.1142/9789814556927_0004

Efficiency-Limiting Processes in Low-Bandgap Polymer:Perylene Diimide Photovoltaic Blends
journal, August 2014


Film Morphology of High Efficiency Solution-Processed Small-Molecule Solar Cells
journal, May 2013


Charge Photogeneration for a Series of Thiazolo-Thiazole Donor Polymers Blended with the Fullerene Electron Acceptors PCBM and ICBA
journal, February 2013


Understanding the Reduced Efficiencies of Organic Solar Cells Employing Fullerene Multiadducts as Acceptors
journal, February 2013


Fullerenecrystallisation as a key driver of charge separation in polymer/fullerene bulk heterojunction solar cells
journal, January 2012


Effect of Morphology on Ultrafast Free Carrier Generation in Polythiophene:Fullerene Organic Solar Cells
journal, October 2010


Ultrafast Exciton Dissociation Followed by Nongeminate Charge Recombination in PCDTBT:PCBM Photovoltaic Blends
journal, June 2011


The Effect of Solvent Additives on Morphology and Excited-State Dynamics in PCPDTBT:PCBM Photovoltaic Blends
journal, June 2012


Correlating Structure with Function in Thermally Annealed PCDTBT:PC70BM Photovoltaic Blends
journal, February 2012


The Impact of Polymer Regioregularity on Charge Transport and Efficiency of P3HT:PCBM Photovoltaic Devices
journal, May 2010


Works referencing / citing this record:

In Situ Analysis of Solvent and Additive Effects on Film Morphology Evolution in Spin-Cast Small-Molecule and Polymer Photovoltaic Materials
journal, May 2018


A Simple but Efficient Small Molecule with a High Open Circuit Voltage of 1.07 V in Solution-Processable Organic Solar Cells
journal, January 2018


Fully Roll-to-Roll Printed P3HT/Indene-C60-Bisadduct Modules with High Open-Circuit Voltage and Efficiency
journal, January 2018


MnCo 2 O 4+x nanowire arrays grown on carbon sponge: improved electrochemical and catalytic performances
journal, January 2019