In order to predict the quantum efficiency of a organic photovoltaic (OPV) devices, modeling and simulation approach can be used. The preparation of three computation parts are needed to predict the external and internal quantum efficiency of OPV devices. The morphology modeling, exciton dissociation and charge transport are the three important parts to be modeled for performance evaluation. We focus on a bulk hetero-junction (BHJ) OPV devices since it is known to achieve high quantum efficiency because of accelerating exciton dissociation efficiency.
It has been known that the performance of organic systems is highly relied on morphology of organic materials. In particular, the domain size and the percolation paths in morphology are critical factor to determine the performance of the organic photovoltaic system.
Mechanism and Device SimulationEdit
The generate exciton is dissociated at the interface of a p-material and a n-material. If the interface area is large, the exciton dissociation efficiency becomes large. In order to enlarge the interface area, the bulk hetero-junction morphology is preferred to the planar hetero-junction morphology. The later morphology is better for charge extraction while the former morphology can generate chargers much effectively. If we can design the trap loss in the morphology is smaller, the bulk hetero-junction (BHJ) morphology can be used a good approach.
Charge extraction is started after exciton is dissociated to an hole and an electron at the interface. The hole and charge can meet again at the interface area during they are going to the corresponding electrodes respectively. The recombination can be occurred if holes and electrons are met at the interface again and again. If an electron meet an hole in the other side of the interface, they can recombine with an probability. The recombination can be a loss factor for charge extraction stage. Moreover, because of non uniformity of the morphology, the dissociated hole sand electrons can not move toward the electrodes. In this case, trap effect is happened. This charge trap reduces the charge extraction efficiency.
Realistic modeling for OPV devicesEdit
Currently, theoretical modeling is used for OPV morphology modeling. Theoretical models have limiting factors such as difference with the original data because of inaccurate parameters and/or inaccurate formulations.
I changed the color of the title to be light blue since the bright blue supported in this editor is too fine.
I found that there are many people who is interested in OPV research. Organic material based device is interesting now but not easy to complete the research to be reached a reasonable performing level.
Interestingly, I can edit my blog article even in my pad. I thought that it is not easy to edit my web articles in the pad especially through web browser.
I can edit this article in an off-line blog editting tool as well as web edtion.