Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Random Copolymers Allow Control of Crystallization and Microphase Separation in Fully Conjugated Block Copolymers

Journal Article · · Macromolecules
 [1];  [2];  [3];  [2];  [2];  [4];  [4];  [3];  [2];  [5]
  1. Pennsylvania State Univ., University Park, PA (United States); New Mexico Tech, Socorro, NM (United States)
  2. Pennsylvania State Univ., University Park, PA (United States)
  3. Univ. of Tennessee, Knoxville, TN (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
  5. Pennsylvania State Univ., University Park, PA (United States); Pennsylvania State Univ., University Park, PA (United States). Materials Research Inst.

Thin films of fully conjugated donor–acceptor block copolymers composed of an electron donating block and an electron accepting block can be used as single component photoactive layers in organic photovoltaic (OPV) devices. In order to realize their full potential, control over microphase separation and thin-film morphology are critical. In conjugated block copolymer systems where one or more blocks can crystallize, the morphological evolution is governed by the competition between microphase separation and crystallization. In this work, we control crystallization of fully conjugated block copolymers with a random copolymer block. Additionally, we suppress the crystal packing of poly(3-hexylthiophene-2,5-diyl) (P3HT) through the insertion of a small number of 3-octylthiophene (3OT) units within the chains, yielding poly(3-hexylthiophene-2,5-diyl-random-3-octylthiophene-2,5-diyl) (P[3HT-r-3OT]). Furthermore, while crystallization of P3HT dominates the morphology and prevents microphase separation in poly(3-hexylthiophene-2,5-diyl)-block-poly((9,9-dioctylfluorene-2,7-diyl)-alt-(4,7-di(thiophene-2-yl)-2,1,3-benzothiadiazole)-5',5"-diyl) (P3HT-b-PFTBT), modest levels of 3OT suppress crystallization in P[3HT-r-3OT]-b-PFTBT, and permit microphase separation. Thus, we demonstrate that incorporating a random copolymer into a donor–acceptor block copolymer can increase control over microphase separation and lead to enhanced performance in OPV devices.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); US Office of Naval Research (ONR); National Science Foundation (NSF)
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
1656476
Journal Information:
Macromolecules, Journal Name: Macromolecules Journal Issue: 21 Vol. 51; ISSN 0024-9297
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English

References (73)

Tuning the Electrical Conductivity and Self-Assembly of Regioregular Polythiophene by Block Copolymerization: Nanowire Morphologies in New Di- and Triblock Copolymers We gratefully acknowledge support from the NSF (CHE-9807707). journal January 2002
Linking Group Influences Charge Separation and Recombination in All-Conjugated Block Copolymer Photovoltaics journal August 2015
Controlling the Field-Effect Mobility of Regioregular Polythiophene by Changing the Molecular Weight journal September 2003
Amphiphilic Diblock Copolymer Compatibilizers and Their Effect on the Morphology and Performance of Polythiophene:Fullerene Solar Cells journal January 2006
All-Polymer Solar Cells Based on Absorption-Complementary Polymer Donor and Acceptor with High Power Conversion Efficiency of 8.27% journal December 2015
Connecting the Mechanical and Conductive Properties of Conjugated Polymers journal December 2017
End-group composition of poly(3-hexylthiophene)s prepared by in situ quenching of the grignard metathesis polymerization: Influence of additives and reaction conditions journal April 2012
On the morphology of polymer-based photovoltaics journal March 2012
Organic solar cell optimizations journal March 2005
Characterization of the mesoscopic structure in the photoactive layer of organic solar cells: A focused review journal January 2013
The effect of post-processing treatments on inflection points in current–voltage curves of roll-to-roll processed polymer photovoltaics journal December 2010
Molecular Rectification in Conjugated Block Copolymer Photovoltaics journal March 2016
Challenges and Opportunities in the Development of Conjugated Block Copolymers for Photovoltaics journal September 2015
Molecular Origin of Photovoltaic Performance in Donor- block -Acceptor All-Conjugated Block Copolymers journal October 2015
Photovoltaic Performance of Block Copolymer Devices Is Independent of the Crystalline Texture in the Active Layer journal June 2016
Regioregularity-Driven Morphological Transition of Poly(3-hexylthiophene)-Based Block Copolymers journal February 2017
Glass Transition Temperature of Conjugated Polymers by Oscillatory Shear Rheometry journal June 2017
Compatibilization of All-Conjugated Polymer Blends for Organic Photovoltaics journal July 2016
Morphology, Crystal Structure and Charge Transport in Donor–Acceptor Block Copolymer Thin Films journal December 2014
In Situ Formation of Pyridyl-Functionalized Poly(3-hexylthiophene)s via Quenching of the Grignard Metathesis Polymerization: Toward Ligands for Semiconductor Quantum Dots journal November 2012
Bulk Heterojunction Solar Cells: Morphology and Performance Relationships journal May 2014
Facile Synthesis of Well-Defined Block Copolymers Containing Regioregular Poly(3-hexyl thiophene) via Anionic Macroinitiation Method and Their Self-Assembly Behavior journal September 2007
Controlling Phase Separation and Optical Properties in Conjugated Polymers through Selenophene−Thiophene Copolymerization journal June 2010
Poly(3-alkylthiophene) Diblock Copolymers with Ordered Microstructures and Continuous Semiconducting Pathways journal June 2011
A Modular Strategy for Fully Conjugated Donor–Acceptor Block Copolymers journal September 2012
Understanding S-Shaped Current–Voltage Characteristics in Organic Solar Cells Containing a TiO x Interlayer with Impedance Spectroscopy and Equivalent Circuit Analysis journal July 2012
Power-law-like stress relaxation of block copolymers: disentanglement regimes journal March 1993
Liquid Crystalline Regioregular Semifluoroalkyl-Substituted Polythiophenes journal September 2000
Rheology of ordered and disordered symmetric poly(ethylenepropylene)-poly(ethylethylene) diblock copolymers journal April 1990
Modes of Crystallization in Block Copolymer Microdomains:  Breakout, Templated, and Confined journal March 2002
Signatures of the Order−Disorder Transition in Copolymers with Quenched Sequence Disorder journal October 2004
Toward High-Performance Polymer Solar Cells:  The Importance of Morphology Control journal March 2007
Crystalline Random Conjugated Copolymers with Multiple Side Chains: Tunable Intermolecular Interactions and Enhanced Charge Transport and Photovoltaic Properties journal April 2010
Tuning Polythiophene Crystallization through Systematic Side Chain Functionalization journal October 2010
Poly(3-hexylthiophene)- block -poly(pyridinium phenylene)s: Block Polymers of p- and n-Type Semiconductors journal April 2011
Polythiophene- block -polyfluorene and Polythiophene- block -poly(fluorene- co -benzothiadiazole): Insights into the Self-Assembly of All-Conjugated Block Copolymers journal February 2011
Polymer Crystallization of Partially Miscible Polythiophene/Fullerene Mixtures Controls Morphology journal July 2011
Self-Assembly of Poly(3-dodecylthiophene)- block -poly(methyl methacrylate) Copolymers Driven by Competition between Microphase Separation and Crystallization journal June 2012
Synthesis of Perfluoroalkyl End-Functionalized Poly(3-hexylthiophene) and the Effect of Fluorinated End Groups on Solar Cell Performance journal December 2012
Phase Separation in the Melt and Confined Crystallization as the Key to Well-Ordered Microphase Separated Donor–Acceptor Block Copolymers journal May 2013
All-Polymer Solar Cells Based on Fully Conjugated Block Copolymers Composed of Poly(3-hexylthiophene) and Poly(naphthalene bisimide) Segments journal December 2012
Structural Factors That Affect the Performance of Organic Bulk Heterojunction Solar Cells journal July 2013
A One-Step Strategy for End-Functionalized Donor–Acceptor Conjugated Polymers journal August 2013
Theory of Microphase Separation in Block Copolymers journal November 1980
Synthesis, Properties, and Tunable Supramolecular Architecture of Regioregular Poly(3-alkylthiophene)s with Alternating Alkyl and Semifluoroalkyl Substituents journal June 2008
Crystalline Diblock Conjugated Copolymers: Synthesis, Self-Assembly, and Microphase Separation of Poly(3-butylthiophene)- b -poly(3-octylthiophene) journal March 2009
Nanostructure Formation in Poly(3-hexylthiophene- block -3-(2-ethylhexyl)thiophene)s journal August 2009
Employing MALDI-MS on Poly(alkylthiophenes):  Analysis of Molecular Weights, Molecular Weight Distributions, End-Group Structures, and End-Group Modifications journal September 1999
Signatures of Multiphase Formation in the Active Layer of Organic Solar Cells from Resonant Soft X-ray Scattering journal February 2013
Ternary Photovoltaic Blends Incorporating an All-Conjugated Donor–Acceptor Diblock Copolymer journal November 2011
Conjugated Block Copolymer Photovoltaics with near 3% Efficiency through Microphase Separation journal May 2013
Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells journal November 2014
Flexible, highly efficient all-polymer solar cells journal October 2015
Influence of blend microstructure on bulk heterojunction organic photovoltaic performance journal January 2011
High work-function hole transport layers by self-assembly using a fluorinated additive journal January 2014
Mixed interlayers at the interface between PEDOT:PSS and conjugated polymers provide charge transport control journal January 2015
‘Blocky’ donor–acceptor polymers containing selenophene, benzodithiophene and thienothiophene for improved molecular ordering journal January 2015
Recent research progress of polymer donor/polymer acceptor blend solar cells journal January 2016
Supramolecular block copolymer photovoltaics through ureido-pyrimidinone hydrogen bonding interactions journal January 2016
Chain conformations and phase behavior of conjugated polymers journal January 2017
Parallel bulk heterojunction photovoltaics based on all-conjugated block copolymer additives journal January 2016
Tuning the synthesis of fully conjugated block copolymers to minimize architectural heterogeneity journal January 2017
Rheological properties and the mechanical signatures of phase transitions in weakly-segregated rod-coil block copolymers journal January 2009
Synthesis of C60-end capped P3HT and its application for high performance of P3HT/PCBM bulk heterojunction solar cells journal January 2010
Morphology of polymer-based bulk heterojunction films for organic photovoltaics journal January 2011
Direct measurements of exciton diffusion length limitations on organic solar cell performance journal January 2012
Photovoltaic enhancement of organic solar cells by a bridged donor-acceptor block copolymer approach journal January 2007
Block Copolymers—Designer Soft Materials journal February 1999
S-shaped current-voltage characteristics of organic solar devices journal September 2010
Viscoelastic behavior of cubic phases in block copolymer melts journal January 1999
Dynamics of Block Copolymers: Theory and Experiment journal August 1996
Block Copolymer Thermodynamics: Theory and Experiment journal October 1990
Control of thermal and optoelectronic properties in conjugated poly (3-alkylthiophenes) journal June 2014

Cited By (2)

Synthesis of a soluble adenine-functionalized polythiophene through direct arylation polymerization and its fluorescence responsive behavior journal January 2020
Structural origins of the electronic properties of materials via time-resolved infrared spectroscopy journal January 2019

Similar Records

An experimental and computational study of donor-linker-acceptor block copolymers for organic photovoltaics
Journal Article · Fri Aug 24 00:00:00 EDT 2018 · Journal of Polymer Science. Part B, Polymer Physics · OSTI ID:1474418

Molecular origin of photovoltaic performance in donor-block-acceptor all-conjugated block copolymers
Journal Article · Mon Nov 02 23:00:00 EST 2015 · Macromolecules · OSTI ID:1245027