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Quantitative Correlation of Perovskite Film Morphology to Light Emitting Diodes Efficiency Parameters
Author(s) -
Kumawat Naresh K.,
Jain Nakul,
Dey Amrita,
Narasimhan K. L.,
Kabra Dinesh
Publication year - 2017
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201603219
Subject(s) - materials science , perovskite (structure) , thin film , photoluminescence , optoelectronics , diode , light emitting diode , yield (engineering) , brightness , charge carrier , electroluminescence , optics , nanotechnology , composite material , layer (electronics) , chemical engineering , physics , engineering
This paper reports quantitative correlation of CH 3 NH 3 PbBr 3 (MAPbBr 3 ) thin film morphology to light emitting diode efficiency parameters. Sequential (spin coating) deposition is used for highly reproducible and dense film morphology of MAPbBr 3 thin‐film. In this fabrication process using an orthogonal solvent approach, control of morphology, coverage, thickness, and optical properties in these compact thin‐films is demonstrated. Optical studies show direct correlation between morphology to dynamics of photoluminescence (PL) and absolute PL yield. Perovskite light emitting diodes (PeLEDs) are fabricated from these films to find the best ratio of PbBr 2 versus MABr for optimal performance. This study demonstrates PeLEDs with high brightness, ≈1050 cd m −2 at 4.7 V (luminance efficiency ≈0.1 cd A −1 ), for optimal thin‐film process with state‐of‐the‐art device performance. This quantitative analysis suggests that these state‐of‐the‐art PeLEDs suffer from poor charge carrier balance (≈2%) and out‐coupling efficiency (≈6%). Interestingly, charge carrier balance and PL yield together can explain the change in PeLED efficiency modulation with film morphology. Studies on single carrier devices show that these PeLEDs are electron current dominated and charge carrier balance increases with operating bias voltage.