scholarly journals Avoiding trap states in poly(n-vinylcarbazole) thin films

2012 ◽  
Vol 13 (12) ◽  
pp. 2843-2849 ◽  
Author(s):  
K.A.S. Araujo ◽  
P.S.S. Guimarães ◽  
L.A. Cury ◽  
L. Akcelrud ◽  
D. Sanvitto ◽  
...  
Keyword(s):  
Thin Films ◽  
Trap States

Photophysical Properties of CdS Nanoparticles in Thin Films for Opto-Chemical Sensing

2004 ◽  
Vol 820 ◽  
Author(s):  
Elena A. Guliants ◽  
Barbara A. Haruff ◽  
James R. Gord ◽  
Christopher E. Bunker
Keyword(s):  
Thin Films ◽  
Organic Compounds ◽  
Protective Coatings ◽  
Photophysical Properties ◽  
Sol Gel ◽  
Liquid Solution ◽  
Optical Signal ◽  
Cds Nanoparticles ◽  
Trap States ◽  
Post Synthesis

AbstractIn recent years, II-VI compound semiconductor nanoparticles synthesized in a liquid solution have been shown to possess unique optoelectronic properties which are highly attractive for the fabrication of various sensors based on the optical signal readout scheme. The challenge has been to immobilize these nanoparticles into films on solid surfaces, i.e. on a chip, so that they do not suffer any property deterioration as a sensing medium. In the presented work, synthesis of CdS nanoparticles in reverse micelle solution using AOT surfactant as a stabilizer has led to particles with relatively bright photoemission identified as originating from both shallow and deep traps inside the bandgap. Moreover, slightly altering the preparation procedure has produced samples with two distinctive crystal structures. Both types of CdS nanoparticles suspended in commonly utilized solvents such as chloroform and hexane were subject to chemical quenching when various organic compounds were introduced into the solution, demonstrating the sensitivity of trap states to their chemical environment. However, the two structures have shown very different optical properties. While post-synthesis treatment had no effect on one type of particle, the other type was able to undergo a photochemical reaction via prolonged UV irradiation, which resulted in an increased luminescence quantum yield ÖL from 2% to 14%. The same particle type was also responsive to thermal treatment, showing even higher values of ÖL (∼40%). The CdS/AOT particles have been cast into thin films by spin-coating on a Si wafer. Coating parameters have been investigated in order to achieve optimal control over the film thickness, uniformity, overall film durability, etc. These nanostructured films capped with various porous polymeric and sol-gel protective coatings were exposed to a series of organic compounds. Photoluminescence data collected for these samples served for identification of the compounds and their concentrations. This paper offers the discussion of photophysical response in CdS nanoparticle-based thin films with respect to development of novel nanostructured opto-chemical sensors.

Pentacene Thin-film Transistors Fabricated with a Simple Solution Process

2006 ◽  
Vol 937 ◽  
Author(s):  
Yutaka Natsume ◽  
Takashi Minakata
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thin Film Transistors ◽  
Carrier Mobility ◽  
Solution Process ◽  
Simple Solution ◽  
Trap States ◽  
Solution Processed ◽  
High Crystallinity ◽  
Transfer Characteristics

ABSTRACTWe have succeeded in developing a simple solution process of pentacene thin films without particular precursor materials. High crystallinity and large plate-like grains of the solution-processed thin films were observed with several analyses. The solution-processed pentacene thin-film transistors (TFTs) were also fabricated and exhibited good transfer characteristics with maximum carrier mobility above 1 cm2/Vs. The solution-processed TFTs also indicated a steep subthreshold swing and high stability of the threshold voltage against the storage in the atmosphere. The trap states and the bulk carrier density in the films were evaluated from the transfer characteristics by using the analytical model. We considered that these good properties could be attributed to the high crystallinity and the large grains of the solution-processed thin films.

scholarly journals Efficient Photo- and Electroluminescence by Trap States Passivation in Vacuum-Deposited Hybrid Perovskite Thin Films

2018 ◽  
Vol 10 (42) ◽  
pp. 36187-36193 ◽  
Author(s):  
Benedikt Dänekamp ◽  
Nikolaos Droseros ◽  
Francisco Palazon ◽  
Michele Sessolo ◽  
Natalie Banerji ◽  
...  
Keyword(s):  
Thin Films ◽  
Trap States ◽  
Hybrid Perovskite

Electrical Properties of Silicon Nitride Thin Films Fabricated by ECR PECVD at Room Temperature

1992 ◽  
Vol 284 ◽  
Author(s):  
Yoo-Chan Jeon ◽  
Hoyoung Lee ◽  
Seung-Ki Joo
Keyword(s):  
Thin Films ◽  
Silicon Nitride ◽  
Electrical Properties ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Silicon Substrates ◽  
Trap States ◽  
Dominant Conduction Mechanism ◽  
Frenkel Emission ◽  
New Interpretation

ABSTRACTSilicon nitride thin films were deposited on single crystalline silicon substrates at room temperature by ECR PECVD with SiH4 and N2 as source gases and the electrical properties were analyzed. The dominant conduction mechanism in a high field was Poole-Frenkel emission. A ledge in I-V curve was observed in the first voltage ramp and it was found to originate from the field reduction at the injecting electrode due to the charge trapped in deep traps in the film. It also turned out that the ledge is a characteristic of monopolar conduction. A new interpretation of the current at low field — tunneling into trap states — was proposed and the current variations according to the field and temperature could be well explained.

scholarly journals Trap States Impact Photon Upconversion in Rubrene Sensitized by Lead Halide Perovskite Thin Films

2019 ◽  
Author(s):  
Sarah Wieghold ◽  
Alexander S. Bieber ◽  
Zachary A. VanOrman ◽  
Juan-Pablo Correa-Baena ◽  
Lea Nienhaus
Keyword(s):  
Thin Films ◽  
Trap States ◽  
Halide Perovskite ◽  
Lead Halide

Energetics of mer/fac isomers in metal tris(8-hydroxyquinoline) chelates: Implications on charge conduction in organic light-emitting devices

2003 ◽  
Vol 771 ◽  
Author(s):  
Kim F. Ferris ◽  
Linda S. Sapochak ◽  
Deanna Rodovsky ◽  
Paul E. Burrows
Keyword(s):  
Thin Films ◽  
Metal Ion ◽  
Trap States ◽  
Trap State ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Electron Correlation Effects ◽  
The Difference ◽  
Structure Calculations

AbstractElectronic structure calculations for the mer and fac-isomers of aluminum tris (8-hydroxyquinoline) (Alq3) and the methyl-substituted series, nMeq3Al (n = 3 - 7) are presented. From these data, we estimate their relative abundances in Alq3 thin films and the resultant trap state energies. Ab initio computations performed at the SCF level suggest a significantly higher stability (6 - 7.5 kcal/mol) of the mer-isomer over the facial form, whereas MP2 treatment of electron correlation effects lowers the difference to (4 - 4.5 kcal/mol). Substitution of the Al+3 metal ion with the larger ions Ga+3 and In+3 increases the energetic preference of the meridianal form by 2.7 kcal/mol and decreases it by 0.8 kcal/mol, respectively. Trap state energies calculated by previously proposed methodologies show little difference between mer and fac trap states. These results suggest that the existence of the facial isomer in thin films of metal trisquinolates is unlikely to significantly affect charge conduction.

Study on Structural and Optical Properties of Sb2S3 and CdI2 Composite Thin Films Deposited by Thermal Vapor Deposition

2018 ◽  
Vol 17 (04) ◽  
pp. 1760033 ◽  
Author(s):  
Vikas Lahariya ◽  
Sumeet Kumar
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Vapor Deposition ◽  
Visible Region ◽  
Trap States ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Composite Thin Films ◽  
Three Samples ◽  
Thermal Vapor Deposition

Thin films of Sb2S3 and CdI2 composites were deposited by thermal vapor deposition method on a glass substrate. The structural and optical properties have been investigated as a function of the film thickness. Three samples were deposited with thickness of 160[Formula: see text]nm, 210[Formula: see text]nm and 380[Formula: see text]nm. The samples were characterized by X-ray diffraction (XRD), UV–visible (UV–Vis) absorption spectroscopy and photoluminescence (PL) spectroscopy. The XRD result confirms the orthorhombic structure of Sb2S3 peaks. The bigger crystals are formed with the increase of the thickness of the film. The band gaps of the deposited composite thin films were found to be in range 2.17–1.48[Formula: see text]eV and suggest the possibility of band gap tunability in the visible region with the changing the thickness of the film. The PL study reveals the intense emission due to band to band recombination with emission in the red region corresponding to trap states.

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