Oğuz KÖYSAL, Gülsüm KOCAKÜLAH, Aliye KAHYAOĞLU, Mert YILDIRIM

CdTe Kuantum Noktası Katkısının E63, E7 ve SCLP Sıvı Kristal Malzemelerin Akım-Voltaj Karakteristikleri Üzerine Etkisi

Nanometre boyutlarındaki kuantum noktalarının (KN) özellikle de konuk-konak bazlı hibrit yapılarda kullanımı yapıların elektro-optik özelliklerinde iyileşmeler ortaya koymuş, dolayısıyla da güncel çalışmaların hatırı sayılı bir kısmının odak noktası KN katkısı yoluyla yapıda iyileştirmeler sağlama üzerine olmuştur. Bu çalışmada CdTe KN katkısının E63, E7 ve SCLP gibi sıvı kristal malzemelerin akım-voltaj karakteristikleri üzerindeki etkileri incelenmiştir. Akım tüm numuneler için QD katkısıyla birlikte artmış fakat en iyi gelişme E7 için elde edilmiştir. Bu sebeple E7 ve KN katkılı E7 yapılarının akım-voltaj karakteristikleri ayrıca morötesi ışık altında incelenmiştir. Her iki yapı için de elektron-deşik çiftlerinin üretiminden dolayı artan morötesi ışık şiddetiyle birlikte akımın arttığı tespit edilmiştir. Fotoakımın ışık gücüne bağlılığı KN katkısının yapıdaki rekombinasyon mekanizmasını etkilemediğini ortaya koymuştur. Öte yandan KN katkılı E7’nin morötesi ışık duyarlılığı E7’ye kıyasla yaklaşık iki kat fazla elde edilmiştir. Böylece, CdTe KN katkısının E7’nin karanlıkta ve morötesi ışık altındaki akım-voltaj ve fotoiletkenlik karakteristiklerine hatırı sayılır katkıda bulunduğu sonucuna varılmıştır.

Anahtar Kelimeler:

Kuantum noktaları (KN), Sıvı kristaller, Akım-Voltaj karakteristiği, Fotoiletkenlik

Effects of CdTe Quantum Dot Dispersal on Current-Voltage Characteristics in Liquid Crystalline Mediums of E63, E7 and SCLP

The usage of nano-sized quantum dots (QDs) particularly in guest-host based hybrid mediums revealed enhancements in electro-optical properties of the mediums, therefore the focus of considerable amount of contemporary studies has been about dispersal of QDs for improvements in medium. This study investigates the effects of CdTe QD dispersal on current-voltage characteristics of some liquid crystalline materials such as E63, E7 and SCLP. Current is increased for all samples due to QD dispersal, however the best improvement is obtained for E7. Hence, current-voltage characteristics of E7 and QD dispersed E7 mediums were also investigated under UV light exposure. Current values of both mediums were found to increase with increasing UV light power due to generation of electron-hole pairs. Photocurrent’s dependence on light power revealed that QD dispersal does not affect recombination mechanism in the medium. On the other hand, UV light responsivity of QD dispersed E7 was obtained approximately twice of that of E7. Thus, it was concluded that CdTe QDs make considerable contribution to current-voltage and photoconductivity characteristics of E7 in dark and under UV light illumination.

Keywords:

Quantum Dots (QDs), Liquid crystals, Current-voltage characteristics, Photoconductivity,

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