Efficiency Improvement of Photovoltaic integrated Organic Light Emitting Diodes by Applying Optical Filters
Date Issued
2012
Date
2012
Author(s)
Hsu, Wei-En
Abstract
Organic light emitting diode (OLED) is becoming a major technique for display technology due to many properties such as self-emissive, fast response time and flexible application. However, poor outdoor contrast ratio of OLED is an important issue to be discussed. Therefore, many efforts were devoted into related researches, such as integrating polarizer and reflective liquid crystal with OLED. Recently, due to the promotion of environmental protection consciousness, an energy-recycling device—thin-film solar cell integrated OLED, would become an attractive solution to contrast ratio problem among many other solutions. Although the integrated device of OLED and solar cell would provide contrast ratio enhancement and energy recycling ability, it would also decrease the luminous efficiency to about 50% as compared to the original OLED. This would become an obstacle to develop this eco-friendly technology.
In this thesis, we focus on designing optical filters with a desired spectrum. By enhancing the OLED emission reflection, and suppress other band besides OLED emissive band, the filters would enhance the OLED emission while keep high contrast ratio. This thesis starts from verifying formal research and building optical simulation models, followed by proving assumptions and designing optical filters. In the last part, we made some analysis and discussions about the effect of filters.
By considering optical filters, we discussed two common optical structures, i.e., the distributed Bragg reflector (DBR) and guided mode resonance (GMR) filter. We use analytical solution to obtain ideal reflectivity and suitable bandwidth. For the GMR part, we scan different parameters by using the relationship of parameters and reflection spectrum to obtain an ideal spectrum with a simple structure.
Finally, we compare the two optical filters and discuss the possibility of full color display realization. Moreover, we discuss the possibility of applying the filters for reflective display devices.
Subjects
Organic light emitting diode
optical filter
SDGs
Type
thesis
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