Energies 2013, 6, 5847-5868; doi:10.3390/en6115847
energies
ISSN 1996-1073
www.mdpi.com/journal/energies
Review
Recent Approaches to Controlling the Nanoscale Morphology of
Polymer-Based Bulk-Heterojunction Solar Cells
Wasiu Adebayo Hammed, Rosiyah Yahya, Abdulra’uf Lukman Bola and
Habibun Nabi Muhammad Ekramul Mahmud *
Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia;
E-Mails: hwaasi@gmail.com (W.A.H.); rosiyah@um.edu.my (R.Y.); lbarchem@yahoo.com (A.L.B.)
* Author to whom correspondence should be addressed; E-Mail: ekramul@um.edu.my;
Tel.: +60-1-2348-3672; Fax: +60-3-7967-4193.
Received: 4 July 2013; in revised form: 28 August 2013 / Accepted: 6 September 2013 /
Published: 8 November 2013
Abstract: The need for clean, inexpensive and renewable energy has increasingly turned
research attention towards polymer photovoltaic cells. However, the performance efficiency
of these devices is still low in comparison with silicon-based devices. The recent introduction
of new materials and processing techniques has resulted in a remarkable increase in
power-conversion efficiency, with a value above 10%. Controlling the interpenetrating
network morphology is a key factor in obtaining devices with improved performance.
This review focuses on the influence of controlled nanoscale morphology on the overall
performance of bulk-heterojunction (BHJ) photovoltaic cells. Strategies such as the use of
solvents, solvent annealing, polymer nanowires (NWs), and donor–acceptor (D–A)
blend ratios employed to control the active-layer morphologies are all discussed.
Keywords: bulk-heterojunction; solar cell; active layer; photovoltaic
1. Introduction
The rapid growth in the human population is having an increasing impact on global energy
consumption [1]. The search for alternative sources of energy is continuing, as reserves of fossil fuels,
the current predominant source of energy, are dwindling and their damaging effects are increasing
by the day. Although there are other means of generating clean and renewable energy such as wind,
geothermal and bio-energy, solar energy seems to be the most abundant [2]. Photovoltaic cells or solar
OPEN ACCESS
energies
ISSN 1996-1073
www.mdpi.com/journal/energies
Review
Recent Approaches to Controlling the Nanoscale Morphology of
Polymer-Based Bulk-Heterojunction Solar Cells
Wasiu Adebayo Hammed, Rosiyah Yahya, Abdulra’uf Lukman Bola and
Habibun Nabi Muhammad Ekramul Mahmud *
Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia;
E-Mails: hwaasi@gmail.com (W.A.H.); rosiyah@um.edu.my (R.Y.); lbarchem@yahoo.com (A.L.B.)
* Author to whom correspondence should be addressed; E-Mail: ekramul@um.edu.my;
Tel.: +60-1-2348-3672; Fax: +60-3-7967-4193.
Received: 4 July 2013; in revised form: 28 August 2013 / Accepted: 6 September 2013 /
Published: 8 November 2013
Abstract: The need for clean, inexpensive and renewable energy has increasingly turned
research attention towards polymer photovoltaic cells. However, the performance efficiency
of these devices is still low in comparison with silicon-based devices. The recent introduction
of new materials and processing techniques has resulted in a remarkable increase in
power-conversion efficiency, with a value above 10%. Controlling the interpenetrating
network morphology is a key factor in obtaining devices with improved performance.
This review focuses on the influence of controlled nanoscale morphology on the overall
performance of bulk-heterojunction (BHJ) photovoltaic cells. Strategies such as the use of
solvents, solvent annealing, polymer nanowires (NWs), and donor–acceptor (D–A)
blend ratios employed to control the active-layer morphologies are all discussed.
Keywords: bulk-heterojunction; solar cell; active layer; photovoltaic
1. Introduction
The rapid growth in the human population is having an increasing impact on global energy
consumption [1]. The search for alternative sources of energy is continuing, as reserves of fossil fuels,
the current predominant source of energy, are dwindling and their damaging effects are increasing
by the day. Although there are other means of generating clean and renewable energy such as wind,
geothermal and bio-energy, solar energy seems to be the most abundant [2]. Photovoltaic cells or solar
OPEN ACCESS
