Investigation of Interplay between Polyvinylpyrrolidone Interlayer and Perovskite Composition Affecting the Performance of Perovskite Light Emitting Diode

초록

Device structure and perovskite composition are two of the most important factors for maximizing the efficiency of light emitting diodes with perovskite as the light emitting layer. However, combining the best structures reported does not necessarily lead to better device performance. In the present study, the authors examine the device performance affected by the interplay between polyvinylpyrrolidone (PVP) as the interlayer and cesium (Cs)- or formamidinium (FA)-based perovskite composition (PEA(2)(Cs(0.87)MA(0.13))(4)Pb5Br16 (PEA: phenyl ethyl ammonium cation, MA: methyl ammonium cation) or PEA(2)FA(2)Pb(3)Br(10), respectively). In the case of Cs-based perovskite light-emitting diodes (PeLEDs), PVP improves the formation of perovskite by preventing intermixing at the interface, thereby improving the device efficiency. On the other hand, although PVP is thought to behave similarly on FA-based perovskite, it degrades device efficiency by decreasing hole injection and shifting the charge balance due to its insulating property. Based on the analysis, high efficiency Cs- and FA-based PeLEDs of 12.31 and 24.5 cd A(-1), respectively, are obtained.

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