Modification of Perovskite/Spiro-OMeTAD Interface with Thiol Molecules for the Fabrication of Highly Efficient and Long-Term Stable Perovskite Solar Cells

Abstract

The surface morphology of the perovskite material with surface / boundary defects, high sensitivity to humidity, and ion migration into the cell under operational conditions are among the most important problems of perovskite solar cells. Interfacial engineering is one of the most effective methods against to such problems in perovskite solar cells. In this study, the cells in which thiol derivative 1-phenyl-1H-tetrazole-5-thiol (PT(thiol)) molecules were used as an interfacial layer between perovskite / spiro-OMeTAD have been fabricated. The open circuit voltage (VOC) values of the cells using the interface layer were improved by 40 mV and the efficiency of 19.5% was obtained. This improvement in photovoltaic performance is explained by the passivation of recombination centers on the surface of the perovskite layer and at the grain boundaries; it is also determined that the interface layer contributes to the problem of operational stability. Stability test performing under continuous illumination and 40% relative humidity displayed that the cell including interlayer maintained 75% of its initial efficiency after 300 hours. As a result, PT(thiol) molecules have the potential to provide solution to the stability problem, which is one of the most important problems of perovskite cells; it has also been found to improve cell performance by improving surface properties.

Keywords

• Perovskite solar cells
• Interfacial modification
• 1-phenyl-1H-tetrazole-5-thiol
• Cell stability

Yüksek Verimli ve Uzun Dönem Kararlı Perovskit Güneş Hücrelerinin Üretimi için Perovskit/Spiro-OMeTAD Arayüzeyinin Thiol Molekülleri ile Modifikasyonu

Öz

Perovskit malzemesinin yüzey/sınır kusurları içeren yüzey morfolojisi, yüksek nem hassasiyeti ve operasyonel koşullarda hücre içine doğru meydana gelen iyon göçü perovskit güneş hücrelerinin çözüm bekleyen en önemli problemleri arasındadır. Arayüzey mühendisliği, perovskit güneş hücrelerinde bu tür sorunlara karşı kullanılan en etkili yöntemlerden biridir. Bu çalışmada, thiol türevi 1-phenyl-1H-tetrazole-5-thiol (PT(thiol)) moleküllerinin, perovskit/spiro-OMeTAD arasında arayüzey tabakası olarak kullanıldığı hücrelerinin üretimi gerçekleştirilmiştir. Arayüzey tabakasının kullanıldığı hücrelerin açık devre gerilim (VOC) değerlerinde 40 mV iyileşme sağlanarak %19.5 verim elde edilmiştir. Fotovoltaik performanstaki bu iyileşme perovskit tabakasının yüzeyindeki ve tane sınırlarındaki rekombinasyon merkezlerinin pasivasyonu ile açıklanırken; arayüzey tabakasının operasyonel kararlılık problemine ciddi bir katkı sağladığı da tespit edilmiştir. Sürekli ışınım altında ve %40 nem içeren bir ortamda gerçekleştirilen kararlılık test sonucunda arayüzey tabakalı hücrenin 300 saat sonunda başlangıç veriminin %75’ini koruduğu tespit edilmiştir. Sonuç olarak PT(thiol) moleküllerinin perovskit hücrelerin en önemli sorunlarından biri olan kararlılık problemine çözüm sunma potansiyeli olduğu; aynı zamanda yüzey özelliklerini de iyileştirerek hücre performansını arttırdığı tespit edilmiştir.

Anahtar Kelimeler

• Perovskit güneş hücreleri
• Arayüzey modifikasyonu
• 1-phenyl-1H-tetrazole-5-thiol
• Hücre kararlılığı

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