Electrospun Electroluminescent CsPbBr3 Fibers as Flexible Perovskite Networks for Light‐Emitting Application

Thin-film perovskite light-emitting diodes have gained increasing attention in the last 6 years. With the possibility to process the emitting layer from solution, the way for 1D morphology of the semiconductor for flexible devices is paved. Herein, for the first time single-step fabrication of CsPbBr3@PVP nanofibers in a customized electrospinning process performed under ambient conditions from a water-based precursor solution is reported. The water-based approach allows the incorporation of a conductive polymer into the compound fiber by blending the perovskite precursor ink with commercially available PEDOT:PSS dispersion. The results demonstrate electrospun fiber mats which are stable at ambient conditions for at least 5 months and can be utilized in electroluminescence devices. Photoluminescence studies on the perovskite fibers reveal a blueshift of the emission peak compared to thin films possibly due to the generation of nanocrystals of ≈12 nm by in situ nanocrystal pinning as confirmed by transmission electron microscopy. A proof-of-concept electrically pumped light-emitting device is built with the obtained fiber mat. The perovskite nanofibers offer promising applications in flexible and stretchable optoelectronics.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Universität zu Köln http://dx.doi.org/10.13039/501100008001Peer Reviewe

Strategically constructing 'culture' in Botswana: An analysis of the influential dimensions impacting San children's experiences within formal education

This thesis is an investigation of how 'culture' is engaged by the San, the government of Botswana, and a local non-governmental organization in order to address the current educational concerns of the San. Through an analysis of the various ways 'culture' is strategically employed within Botswana, in relation to discussing San children's experiences within formal education, this thesis argues that 'culture' is constructed by various actors in ways which compliment particular motivations and reflect the current positioning of the San in Botswana