Molecular Self-Assembly Routes to Optically Functional Thin Films: Electroluminescent Multilayer Structures

1997 ◽  
Vol 488 ◽  
Author(s):  
W. Li ◽  
J. E. Malinsky ◽  
H. Chou ◽  
W. Ma ◽  
L. Geng ◽  
...  

AbstractThis contribution describes the use of layer-by-layer self-limiting siloxane chemisorption processes to self-assemble structurally regular multilayer organic LED (OLED) devices. Topics discussed include: 1) the synthesis of silyl-functionalized precursor molecules for hole transport layer (HTL), emissive layer (EML), and electron transport layer (ETL) self-assembly, 2) the use of layer-by-layer self-assembly for ITO electrode modification/passivation/hole-electron balancing in a vapor-deposited device, 3) the microstructure/chemical characterization of HTL self-assembly using a prototype triarylamine precursor, 4) fabrication and properties of a hybrid self-assembled + vapor deposited two-layer LED, 4) fabrication and properties of a fully self-assembled two-layer OLED.

10.26524/jap9 ◽  
2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Jayamurugan P ◽  
Manoharan D ◽  
Ramadevi K ◽  
Upendar Reddy K ◽  
Subba Rao Y V

The nanocolloidal solution has been spin coated on the substrate layer-by-layer, a self-assembly technique has used to form the multilayer thin films. The optical and structural properties of self-assembled multilayer thin films were characterized by UV-visible, photoluminescence, X-ray diffraction and atomic force microscopy


Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 404
Author(s):  
Abdul Sami ◽  
Arsalan Ansari ◽  
Muhammad Dawood Idrees ◽  
Muhammad Musharraf Alam ◽  
Junaid Imtiaz

Perovskite inorganic-organic solar cells are fabricated as a sandwich structure of mesostructured TiO2 as electron transport layer (ETL), CH3NH3PbI3 as active material layer (AML), and Spiro-OMeTAD as hole transport layer (HTL). The crystallinity, structural morphology, and thickness of TiO2 layer play a crucial role to improve the overall device performance. The randomly distributed one dimensional (1D) TiO2 nanowires (TNWs) provide excellent light trapping with open voids for active filling of visible light absorber compared to bulk TiO2. Solid-state photovoltaic devices based on randomly distributed TNWs and CH3NH3PbI3 are fabricated with high open circuit voltage Voc of 0.91 V, with conversion efficiency (CE) of 7.4%. Mott-Schottky analysis leads to very high built-in potential (Vbi) ranging from 0.89 to 0.96 V which indicate that there is no depletion layer voltage modulation in the perovskite solar cells fabricated with TNWs of different lengths. Moreover, finite-difference time-domain (FDTD) analysis revealed larger fraction of photo-generated charges due to light trapping and distribution due to field convergence via guided modes, and improved light trapping capability at the interface of TNWs/CH3NH3PbI3 compared to bulk TiO2.


2009 ◽  
Vol 95 (3) ◽  
pp. 033501 ◽  
Author(s):  
Ming-Ta Hsieh ◽  
Meng-Huan Ho ◽  
Kuan-Heng Lin ◽  
Jenn-Fang Chen ◽  
Teng-Ming Chen ◽  
...  

2020 ◽  
Vol 5 (9) ◽  
pp. 2935-2944 ◽  
Author(s):  
Yuanbao Lin ◽  
Yuliar Firdaus ◽  
Furkan H. Isikgor ◽  
Mohamad Insan Nugraha ◽  
Emre Yengel ◽  
...  

2020 ◽  
Vol 10 (17) ◽  
pp. 6081
Author(s):  
Junekyun Park ◽  
Eunkyu Shin ◽  
Jongwoo Park ◽  
Yonghan Roh

We demonstrated the way to improve the characteristics of quantum dot light emitting diodes (QD-LEDs) by adding a simple step to the conventional fabrication process. For instance, we can effectively deactivate the surface defects of quantum dot (QD) (e.g., CdSe/ZnS core-shell QDs in the current work) with the SiO bonds by simply mixing QDs with hexamethyldisilazane (HMDS) under atmospheric conditions. We observed the substantial improvement of device characteristics such that the current efficiency, the maximum luminance, and the QD lifetime were improved by 1.7–1.8 times, 15–18%, and nine times, respectively, by employing this process. Based on the experimental data (e.g., energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS)), we estimated that the growth of the SiOx on the surface of QDs is self-limited: the SiOx are effective to passivate the surface defects of QDs without deteriorating the intrinsic properties including the color-purity of QDs. Second, we proposed that the emission profiling study can lead us to the fundamental understanding of charge flow in each layer of QD-LEDs. Interestingly enough, many problems related to the charge-imbalance phenomenon were simply solved by selecting the combination of thicknesses of the hole transport layer (HTL) and the electron transport layer (ETL).


2018 ◽  
Vol 6 (29) ◽  
pp. 14255-14261 ◽  
Author(s):  
Huan Li ◽  
Guoqing Tong ◽  
Taotao Chen ◽  
Hanwen Zhu ◽  
Guopeng Li ◽  
...  

A derivative-phase CsPb2Br5 is introduced into inorganic perovskite solar cells, which will effectively eliminate interface defects, lower the energy barrier of electron transport layer and suppress the recombination at the interface of hole transport layer in the devices.


RSC Advances ◽  
2016 ◽  
Vol 6 (76) ◽  
pp. 72462-72470 ◽  
Author(s):  
Jingling Li ◽  
Hu Jin ◽  
Kelai Wang ◽  
Dehui Xie ◽  
Dehua Xu ◽  
...  

In this work, all-solution processed, multi-layer yellow QLEDs, consisting of a hole transport layer of poly(9-vinylcarbazole), emissive layer of ligand exchanged CuInS2/ZnS QDs, and electron transport layer of ZnO nanoparticles, are fabricated.


2016 ◽  
Vol 16 (4) ◽  
pp. 3368-3372 ◽  
Author(s):  
Shuri Sato ◽  
Masashi Takata ◽  
Makoto Takada ◽  
Hiroyoshi Naito

The degradation of bilayer organic light-emitting diodes (OLEDs) with a device structure of N, N′-di(1-naphthyl)-N, N′-diphenylbenzidine (α-NPD) (hole transport layer) and tris-(8-hydroxyquinolate)aluminum (Alq3) (emissive layer and electron transport layer) has been studied by impedance spectroscopy and device simulation. Two modulus peaks are found in the modulus spectra of the OLEDs below the electroluminescence threshold. After aging of the OLEDs, the intensity of electroluminescence is degraded and the modulus peak due to the Alq3 layer is shifted to lower frequency, indicating that the resistance of the Alq3 layer is increased. Device simulation reveals that the increase in the resistance of the Alq3 layer is due to the decrease in the electron mobility in the Alq3 layer.


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