Effect of Liquid Crystal and Magnetic Field on The Thermoelectric Properties of Polythiophene/PEDOT Composite

Öz

Small heat sources such as body heat are sufficient to operate thermoelectric generators produced by using the Seebeck effect. Therefore, thermoelectric materials that convert small temperature difference into energy have become very important today. In this study, polythiophene (PTh) particles were synthesized in the presence and absence of magnetic field in the presence of liquid crystal for the first time, then PTh/PEDOT composites were synthesized by polymerizing 3,4-ethylenedioxy thiophene (EDOT) on PTh and their thermoelectric properties were investigated. Seebeck coefficient and electrical conductivity were measured from thin films of synthesized polymers and their power factors were calculated. While the magnetic field did not change the electrical conductivity much, the Seebeck coefficient increased the absolute value and reduced the particle sizes. The highest electrical conductivity, Seebeck coefficient and power factor values were taken from the PTHm sample synthesized under magnetic field with 0.6 S/cm, -540 µV/K and 17.5 µW/mK², respectively. FTIR, UV-vis. analysis and DLS measurement of PTh and PTh/PEDOT composites were made.

Anahtar Kelimeler

• Thermoelectric
• Seebeck coefficient
• Polythiophene
• Poly(3
• 4‐ethylenedioxythiophene)

Politiyofen/PEDOT Kompozitinin Termoelektrik Özelliklerine Sıvı Kristal ve Manyetik Alanın Etkisi

Öz

Seebeck etkisinden yararlanılarak üretilen termoelektrik jeneratörleri çalıştırmak için vücut ısısı gibi küçük ısı kaynakları yeterlidir. Bu nedenle, küçük sıcaklık farkını enerjiye çeviren termoelektrik malzemeler günümüzde oldukça önemli hale gelmiştir. Bu çalışmada, ilk defa sıvı kristal varlığında, manyetik alanlı ve manyetik alansız ortamda önce politiyofen (PTh) partikülleri daha sonra PTh üzerine 3,4-etilendioksi tiyofen (EDOT) polimerleştirilerek PTh/PEDOT kompozitleri sentezlenmiş ve termoelektrik özellikleri incelenmiştir. Sentezlenen polimerlerin ince filmlerinden Seebeck katsayısı ve elektriksel iletkenlik ölçülüp güç faktörleri hesaplanmıştır. Manyetik alan, elektriksel iletkenliği çok fazla değiştirmezken, Seebeck katsayısını mutlak değer olarak arttırmış ve partikül büyüklüklerini küçültmüştür. En yüksek elektriksel iletkenlik, Seebeck katsayısı ve güç faktörü değerleri sırasıyla, 0,6 S/cm, -540 µV/K ve 17,5 µW/mK² ile manyetik alan altında sentezlenen PThm örneğinden alınmıştır. Elde edilen PTh ve PTh/PEDOT kompozitlerin FTIR, UV-vis. analizi ve DLS ölçümü yapılmıştır.

Anahtar Kelimeler

• Termoelektrik
• Seebeck Katsayısı
• Politiyofen
• Poli(3,4-etilen dioksitiyofen)

Kaynakça

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