ABSTRACT

Solid-state lighting (SSL) is one of the biggest achievements of the 20th century. It has completely changed our modern life with respect to general illumination (light-emitting diodes), flat devices and displays (organic light-emitting diodes), and small labelling systems (light-emitting electrochemical cells). However, challenges are still present in this field, regarding i) the employment of limited and expensive materials, ii) the lack of a high-quality white light and iii) the need of overall better efficiencies and stabilities. Thus, the main target of this project is to address those challenges concerning the light-emitting diodes. Therefore, we are currently working on the development of polymer coatings based on fluorescent proteins to improve the stability of the novel fluorescent protein-based Hybrid LEDs. A key point in this work is the decoupling of the degradation process occurring in the coating, which includes thermal- and photo-degradation of proteins, and the interactions taking place between the protein and the polymer matrix. The separation of both mechanisms allows the determination of the optimum parameters to enhance the stability and performance of the bio-coating upon constant irradiation. The temperature effect was firstly analyzed by studying the loss of fluorescence emission of the protein upon temperature increase, changing also de pH and nature of solutions in which the protein was embedded. Furthermore, to analyze the photo-degradation, different distances between sample and LED source were studied to determine the minimum distance at which temperature had no effect on the degradation process. Finally, spectroscopic analysis was performed to elucidate the changes taking place upon degradation of the protein.