Ag8SnS6 ve Ag8SnSe6 argirodit bileşiklerinin elektronik, taşınım ve termoelektrik özelliklerinin temel ilkeler ile incelenmesi
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Dosyalar
Tarih
2019
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Namık Kemal Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Termoelektrik sistemler çevre dostu ve yenilenebilir enerji özellikleriyle tercih edilebilir sistemlerdir. Farklı avantajlarıyla termoelektrik enerji uygulamaları soğutma, ısıtma, elektrik üretimi ve iklimlendirme gibi çeşitli alanlarda yaygınlaşma potansiyeli vardır. Termoelektrik metaryellerin verimliliği yüksek elektriksel iletkenlik ve Seebeck katsayısı ve düşük termal iletkenliğe sahip olması gerekmektedir. Aynı anda tüm bu özelliklere sahip malzemeler çok az miktardadır. Ag8SnS6 ve Ag8SnSe6 malzemeleri düşük termal iletkenliğe sahip olduğu bilinen yüksek düzensizliğe sahip yarıiletkenler olup elektronik ta¸sınım özelliklerinden dolayı dikkat çekmektedirler. Bu çalışmada Ag8SnS6 ve Ag8SnSe6 yarıiletkenlerin yapısal, elektronik ve termoelektrik özellikleri temel ilke yöntemleriyle incelenmişve sonuçlar mevcut deneyler ile karşılaştırılmıştır. Hesaplamalar yoğunluk fonksiyonel kuramı ve yarı-klasik Boltzmann taşınım kuramı ile gerçekleştirilmiştir. Örgü sabitleri, hacim modülü, elektronik bant yapıları, toplam ve kısmi durum yoğunlukları ve termoelektrik katsayıları deneyden hiç bir parametre kullanılmadan hesaplanmıştır. Hesaplamalar sonucu elde edilen ZT öngörüleri var olan n-tipi katkılanmış deneylerle uyumlu olup, p-tipi katkılama yapıldığında ZT değerlerinin çok daha yüksek olacağı bulunmuştur
Thermoelectric systems are preferable systems with environmental friendly and renewable energy properties. Thermoelectric power applications with different advantages have the potential to expand in various fields such as cooling, heating, electricity generation and air conditioning. Thermoelectric materials must have high electrical conductivity and high Seebeck coefficient and low thermal conductivity. Few materials exist having all these features at the same time. Ag8SnS6 and Ag8SnSe6 materials are highly disordered semiconductors which are known to have low thermal conductivity and attract attention due to their electronic transport properties. In this study, structural, electronic and thermoelectric properties of Ag8SnS6 and Ag8SnSe6 semiconductors were examined from first principles calculations and the results are compared with the available experiments. The calculations were carried out with density functional theory and semi-classical Boltzmann transport theory. Lattice constants, bulk modulus, electronic band structures, total and partial density of states and thermoelectric coefficients were calculated without using any parameters from the experiments. The predicted ZT are compatible with the existing n-type doped experiments and it was found that the ZT values can be much higher when p-type doping was performed.
Thermoelectric systems are preferable systems with environmental friendly and renewable energy properties. Thermoelectric power applications with different advantages have the potential to expand in various fields such as cooling, heating, electricity generation and air conditioning. Thermoelectric materials must have high electrical conductivity and high Seebeck coefficient and low thermal conductivity. Few materials exist having all these features at the same time. Ag8SnS6 and Ag8SnSe6 materials are highly disordered semiconductors which are known to have low thermal conductivity and attract attention due to their electronic transport properties. In this study, structural, electronic and thermoelectric properties of Ag8SnS6 and Ag8SnSe6 semiconductors were examined from first principles calculations and the results are compared with the available experiments. The calculations were carried out with density functional theory and semi-classical Boltzmann transport theory. Lattice constants, bulk modulus, electronic band structures, total and partial density of states and thermoelectric coefficients were calculated without using any parameters from the experiments. The predicted ZT are compatible with the existing n-type doped experiments and it was found that the ZT values can be much higher when p-type doping was performed.
Açıklama
Anahtar Kelimeler
Ab initio hesaplamalar, gümüş tabanlı yarıiletkenler malzemeler, yoğunluk fonksiyonel kuramı, termoelektrik özellikler, Ab initio calculations, silver based semiconductors, density functional theory, thermoelectric properties
