Electrical, Optical, and Structural Characteristics of CH3NH3PbI3 Perovskite Light‐Emitting Diodes

• Published in: Physica status solidi. A, Applications and materials science Applications and materials science, 2018-10, Vol.215 (20), p.n/a
• Main Authors: Oh, Munsik, Jo, Seung‐Il, Parida, Bhaskar, Singh, Arjun, Ko, Keumjin, Kang, Jae‐Wook, Kim, Hyunsoo
• Format: Article
• Language: English
• Subjects: Bias; Current efficiency; Diodes; Electric potential; ideality factor; Leakage current; light‐emitting diodes; Organic light emitting diodes; perovskite; Perovskites; Pinholes; Quantum efficiency; series resistance; Zinc oxide
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201701014

Electrical, optical, and structural characteristics of perovskite light‐emitting diodes (PeLEDs) are investigated. The PeLED consisting of ITO/ZnO/MAPbI3 (CH3NH3PbI3)/spiro‐OMeTAD/Ag structures shows a peak emission wavelength of 766 nm, turn‐on voltage of 1.7 V, reverse breakdown voltage of −5.4 V, current efficiency of 1.5 × 10−4 cdA−1, maximum luminance of 0.1 cdm−2, and an external quantum efficiency of 0.2% at bias voltage of 3 V (or a current density of 617 mA cm−2). The PeLED also shows a significant output drop at higher bias voltage. According to the analyses of forward J–V curves and structural studies, this could be associated with the anomalously large ideality factor of 12.8 and the high series resistance of 2.8 Ω cm2, that is, the leakage current through parasitic shunt path (possibly through pinholes in the perovskite) and accelerated Joule‐heating result in a significant output degradation. The perovskite light‐emitting diodes (PeLEDs) consisting of ITO/ZnO/MAPbI3 (CH3NH3PbI3)/spiro‐OMeTAD/Ag structures show an external quantum efficiency of 0.2% at bias voltage of 3 V (at 766 nm) and reverse breakdown voltage of −5.4 V. The poor output efficiency is explained in terms of parasitic shunt path (possibly through pinholes in the perovskite) and accelerated Joule‐heating under high bias.