PROJECTS

NATIONAL CAPACITY DEVELOPMENT IN NEW MATERIALS/ NEW TECHNOLOGIES: FOCUS ON POLYMER-BASED SOLAR PV CELL FABRICATION AND CHARACTERIZATION

 INTRODUCTION

 Research and development activities currently going on between NASENI, SHESTCO and Obafemi Awolowo University* in the field of conducting polymers (CPs) have increased in a phenomenological manner in the last 25 years due largely to their wide ranging potentials in electronics and opto-electronic applications, including production of PV cells and OLEDs. Inorganic PV cells of Si (and other materials) though have attractive efficiencies generally better than 12% but their costs are still too high. For instance, BP solar crystalline Si PV cells are about 15% efficient and cost $300/m2 or $2.5/W. Thin films cells based on other prominent materials such as GaAs, CdS, CdTe, CuInS 2 and a-Si have promising potentials, but As, Cd , S are toxic, In is expensive and a-Si are much less stable.

Organic PV cells can be fabricated with non-toxic, environmentally benign, low tech and low cost materials. The most commonly researched CPs are polyanilines (PAni), polypyroles (Ppy), polythiophenes(PTOP), polyphenylenes (PP) and poly (p-phenylene vinylene)s, PPV.

Typically, the operations of an organic based PV cell may be visualized as occurring in 3 basic steps, namely: absorption of light, generation of separate charges at the donor-acceptor interface and selective transport of the charges through the bulk of the device to the appropriate collecting electrodes. With appropriate choice of materials and clever design of multi-layered structures, it is now possible to fabricate PV devices with significantly improved efficiency.

NASENI through one of its centre, the EMDI, has initiated efforts at developing capacity in this new and obviously exciting area of materials.

This work is being coordinated by Dr. Willy O . Siyanbola

The Agency is collaborating with materials experts/ resource persons at the Obafemi Awolowo University, Ile-Ife and the Advanced Physics Laboratory, SHESTCO, Abuja in order to ensure that Nigeria becomes actively involved in the field. Through the DG of the Agency, a number of resource persons have visited the prestigious Princeton Materials Institute to share knowledge and acquire further capabilities under the American NSF/ Africa materials development initiative. A number of these research scientists have since returned to the country.

OBJECTIVES OF THE PROJECT  

• To develop national capability for the production of conducting polymers.
• To develop national capability for the fabrication of polymer-based solar cells and Organic LEDs
• To carry out detailed characterization of the devices particularly their optical and Electrical Characteristics.
• To produce prototypes of such devices.

DEVICE FABRICATION TECHNIQUES AND CHARACTERISATION:

Conjugated polymers can be prepared by different methods ranging from Physical, Chemical or Solvent based techniques. The more compatible techniques with commercial fabrication of polymer electronic circuits are Spin coating, Laser ablation and Ink-jet Printing. Spin coating technique was adopted for the fabrications of the PV cell while the current-voltage characteristics were measured using the HP Semiconductor Analyser. The example presented here was fabricated using the spin coating technique. The work was carried out at the PMI, USA during a recent visit to that institution by a member of our research team.