Identification of Trap States in Perovskite Solar Cells

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• 作者：Andreas Baumann ; Stefan V盲th ; Philipp Rieder ; Michael C. Heiber ; Kristofer Tvingstedt ; Vladimir Dyakonov
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：June 18, 2015
• 年：2015
• 卷：6
• 期：12
• 页码：2350-2354
• 全文大小：264K
• ISSN：1948-7185

文摘

Thermally stimulated current (TSC) measurements are used to characterize electronic trap states in methylammonium lead iodide perovsite solar cells. Several TSC peaks were observed over the temperature range from 20 K to room temperature. To elucidate the origins of these peaks, devices with various organic charge transport layers and devices without transport layers were tested. Two peaks appear at very low temperatures, indicating shallow trap states that are mainly attributed to the PCBM/C₆₀ electron transport bilayer. However, two additional peaks appear at higher temperatures, that is, they are deeper in energy, and are assigned to the perovskite layer. At around T = 163 K, a sharp peak, also present in the dark TSC measurements, is assigned to the orthorhombic鈥搕etragonal phase transition in the perovskite. However, a peak at around T = 191 K is assigned to trap states with activation energies of around 500 meV but with a rather low concentration of 1 脳 10²¹ m^鈥?.