Effect of post-fabrication thermal annealing on Fermi-level pinning phenomenon in metal-pentacene junctions

Jeong, Seong Guk; Park, Hyung-Youl; Lim, Myung Hoon; Jung, Woo Shik; Yu, Hyun Yong; Roh, Yonghan; Park, Jin‐Hong

doi:10.1016/j.orgel.2012.05.030

Cited by 6 publications

(2 citation statements)

References 17 publications

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“…Many previous reports have shown that the physical and chemical characteristics of both polymers and small-molecule organic materials could change noticeably. [28][29][30] The AFM measurement reveals that the employment of Li 2 CO 3 as a dopant in MADN can enhance the thermal stability of the films and smoothen the organic films at relatively high temperatures. The surface roughness results for these four samples are summarized in Table II.…”

Section: Resultsmentioning

confidence: 99%

2-Methyl-9,10-bis(naphthalen-2-yl)anthracene Doped Lithium Carbonate as an Effective Electron Injecting Layer for Both Inverted and Conventional Organic Light-Emitting Diode Structures

Tsai

Liu

Kao

et al. 2020

ECS J. Solid State Sci. Technol.

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High driving voltage, low power efficiency, and insufficient device stability are the most critical complications for organic lightemitting diodes (OLEDs) on their way to practical applications. Particularly in the case of active-matrix organic light emitting device (AMOLED) displays, inferior electron injection from commonly-used ITO electrodes is a critical issue. In this work, 2-Methyl-9,10-bis(naphthalen-2-yl)anthracene doped rubidium carbonate (MADN:Li 2 CO 3 ) is used as an effective electron injecting layer for both inverted and normal bottom-emission organic light-emitting diodes. When the concentration of Li 2 CO 3 -doped MADN is optimized, the device exhibits improved characteristics, including improvements in turn-on voltage, luminance, and efficiency. Ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) analyses reveal an energy level shift in MADN:Li 2 CO 3 , which indicates the Fermi level of MADN is moving close to its lowest unoccupied molecular orbital (LUMO) and therefore facilitating electron injection from ITO. In addition, the AFM measurement showed the morphology of the Li 2 CO 3 -doped MADN films, revealing good thermal stability in the material related to enhanced lifetime. The results unveiled in this work indicate that Li 2 CO 3 :MADN is a promising electron injecting layer for OLEDs with different device structures and provide a vision of the mechanisms behind this phenomenon.

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Section: Resultsmentioning

confidence: 99%

2-Methyl-9,10-bis(naphthalen-2-yl)anthracene Doped Lithium Carbonate as an Effective Electron Injecting Layer for Both Inverted and Conventional Organic Light-Emitting Diode Structures

Tsai

Liu

Kao

et al. 2020

ECS J. Solid State Sci. Technol.

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“…Güllü et al [12] have estimated various electronic parameters of a Schottky diode based on Orange G such as the ideality factor, the series resistance, and the barrier height from the current–voltage ( I–V ) and the capacitance–voltage ( C–V ) measurements. Recently, various authors have studied Schottky diodes based on pentacene using impedance spectroscopy [13], and I–V for electrical and stability performances [14, 15]. Small molecules are expected to be as a promising alternative to their polymeric analogues for organic electronic technology.…”

Section: Introductionmentioning

confidence: 99%

Effect of annealing temperatures on the turn‐on voltage of organic Schottky diode based on DPP(BTFu) ₂

Mansour

Saïdi

Saidi-Amroun

2016

Micro & Nano Letters

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The electrical properties of diketopyrrolopyrrole ethyl‐hexylated (DPP(TBFu)2) thin film sandwich structure of the ITO/DPP(TBFu)2/Al configuration for different annealing temperatures ranging from 40 to 130°C is investigated. The current–voltage characteristics showed an excellent rectifying behaviour of the device, and from which the diode parameters were extracted. It is found that all parameters remain constant upon annealing temperatures, with the exception of the turn‐on voltage. An increase of the turn‐on voltage from an initial value of 1.6–2.08 V is noticed starting from 70 to 100°C, respectively. This fact is attributed to the effect of residual solvent induced defect states that may act as free carriers. Defect states density for the non‐annealed and annealed device at 130°C derived from capacitance–voltage measurements is found to correlate well with the turn‐on voltage. It is found that annealing the device at 130°C results in a smaller concentration of defect states. In addition, it is also found that the annealing process produces the flat band voltage drop, which has a direct impact on the turn‐on voltage.

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Comparison of the role of holes and electrons in hysteresis and threshold voltage stability of organic field effect transistors

Nimmakayala

Sawant

Sudarsan

et al. 2013

Physica Status Solidi (a)

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Electrical measurements on copper phthalocyanine (CuPc)based organic field effect transistors using SiO 2 dielectric revealed hysteresis and threshold voltage instability to be due to the combined effect of both hole-and electron-trapping mechanisms, with the electron-trap density being higher than hole-trap density. Hysteresis was found to increase further after modifying the SiO 2 surface with octadecyltrichlorosilane (OTS) while it reduced drastically after polystyrene (PS) modification. Individual contribution of holes and electrons to hysteresis and the cause of increased/reduced trapping of the same for interface modified devices were identified. The increase in hysteresis with OTS-modified devices was attributed to increase in hole-trap density arising from a larger grain-boundary density of CuPc films. Minimum grainboundary density and efficient removal of trap centers at dielectric/semiconductor interface using PS modification resulted in minimum hysteresis. Comparison of hole-and electron-trap densities estimated for measurements under different ambient conditions, like high humidity conditions and oxygen flow, showed that hole-trap density increased with increase in humidity. Under oxygen flow, hysteresis, and holetrap density were found to reduce considerably, which could be attributed to creation of excess holes that readily fill hole traps, thereby resulting in increased mobile carrier concentrations.

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Effect of post-fabrication thermal annealing on Fermi-level pinning phenomenon in metal-pentacene junctions

Cited by 6 publications

References 17 publications

2-Methyl-9,10-bis(naphthalen-2-yl)anthracene Doped Lithium Carbonate as an Effective Electron Injecting Layer for Both Inverted and Conventional Organic Light-Emitting Diode Structures

2-Methyl-9,10-bis(naphthalen-2-yl)anthracene Doped Lithium Carbonate as an Effective Electron Injecting Layer for Both Inverted and Conventional Organic Light-Emitting Diode Structures

Effect of annealing temperatures on the turn‐on voltage of organic Schottky diode based on DPP(BTFu) ₂

Comparison of the role of holes and electrons in hysteresis and threshold voltage stability of organic field effect transistors

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Effect of post-fabrication thermal annealing on Fermi-level pinning phenomenon in metal-pentacene junctions

Cited by 6 publications

References 17 publications

2-Methyl-9,10-bis(naphthalen-2-yl)anthracene Doped Lithium Carbonate as an Effective Electron Injecting Layer for Both Inverted and Conventional Organic Light-Emitting Diode Structures

2-Methyl-9,10-bis(naphthalen-2-yl)anthracene Doped Lithium Carbonate as an Effective Electron Injecting Layer for Both Inverted and Conventional Organic Light-Emitting Diode Structures

Effect of annealing temperatures on the turn‐on voltage of organic Schottky diode based on DPP(BTFu) 2

Comparison of the role of holes and electrons in hysteresis and threshold voltage stability of organic field effect transistors

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Effect of annealing temperatures on the turn‐on voltage of organic Schottky diode based on DPP(BTFu) ₂