Power spectral density analysis and photoconducting behavior in copper(ii) phthalocyanine nanostructured thin films

Karan, Santanu; Mallik, Biswanath

doi:10.1039/b809648a

Cited by 35 publications

(30 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After annealing process, we obtain more homogenous structure, where grains (with larger diameter) form aggregates and flake-like structure (slightly lower RMS roughness parameter after annealing process). Similar behavior can be observed in the case of thin films deposited at different temperatures of the substrate [28,29]. The variation of RMS roughness and the grain size is smaller at lower temperature but these are significantly higher in case of higher deposition temperatures.…”

Section: Resultssupporting

confidence: 68%

Orientation study of iron phthalocyanine (FePc) thin films deposited on silicon substrate investigated by atomic force microscopy and micro-Raman spectroscopy

Szybowicz

Makowiecki

2011

J Mater Sci

View full text Add to dashboard Cite

In this article, we present temperature and orientation study of iron phthalocyanine (FePc) thin films with different thickness deposited on silicon substrate. The organic thin films were obtained by the quasi-molecular beam evaporation. The micro-Raman scattering spectra of FePc thin layers were investigated in the spectral range 550-1,800 cm -1 using 488-nm excitation wavelength. The Raman scattering and atomic force microscopy studies were performed at room temperature before and after annealing process. Annealing process of thin layers was carried out at 453 K for 6 h. From polarized Raman spectra using surface Raman mapping procedure the information on distribution of polymorphic phases of FePc layers has been carried out. Moreover, the obtained results showed the influence of the annealing process on the ordering of the molecular structure of thin films deposited on silicon substrate. For the very thin layers we did not observe the change of the polymorphic phase but only reordering of the thin layers and change of molecular structure to intermediate phase. Using atomic force microscopy method, we observed arrangement of the thin layers structure connected with the change of roughness of the thin layers after annealing process. The obtained results indicate that the structure of thin layer deposited on silicon substrate is strongly affected by the annealing process.

show abstract

Section: Resultssupporting

confidence: 68%

Orientation study of iron phthalocyanine (FePc) thin films deposited on silicon substrate investigated by atomic force microscopy and micro-Raman spectroscopy

Szybowicz

Makowiecki

2011

J Mater Sci

View full text Add to dashboard Cite

show abstract

“…10, the curve for the 10 nm on the annealed gold substrate is comparable to a 6 nm thick film evaporated on gold at room temperature (see above), hence the substrate temperature does not distinctly affect the molecular orientation in this case. We note however, that distinct changes, in particular of the morphology as a function of the substrate temperature were observed for related systems [59].…”

Section: Distinguishing Between the First Layers And Thin Filmsmentioning

confidence: 90%

Orientation and electronic properties of phthalocyanines on polycrystalline substrates

Peisert

Biswas

Knupfer

et al. 2009

Physica Status Solidi (b)

115

View full text Add to dashboard Cite

We review the molecular orientation of phthalocyanines as representatives of flat, π‐conjugated molecules on different polycrystalline substrates. Thin films with a thickness of ∼10–50 nm are often highly ordered on several substrates. The molecular orientation, however, can be radically different for single crystalline model substrates and for relatively ill defined polycrystalline substrates. Moreover, it is important to distinguish between the growth of the first organic layer(s) at the substrate surface and the growth in films of a thickness of several nanometers: Differently oriented, buried interfacial layers of few monolayers were observed in particular for polycrystalline substrates. The growth mode is discussed in terms of different molecule–molecule and molecule–substrate interactions. Consequences for our understanding of the behavior of such films in devices are considered in context with electronic interface properties. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

show abstract

“…As introduced in the last section of Computational methods and plotted in Figure 2b, the initial C(q) has been determined based on measured RMS roughness for the thin film type and bulk-type and relationship between C(q) and RMS discussed by Flys et al 47 After cycling, experimental studies 54,56,58,63 have reported the RMS roughness would increase. Also, based on the study of surface morphology, 45,46,64 the absolute value of m, of the plot in Figure 2b would increase, and the intercept, I, would be decreased when the RMS roughness is increased. (m, I) values were changed to mimic the effect interface roughening due to battery cycling.…”

Section: Resultsmentioning

confidence: 99%

“…For example, an interface may look like contact perfectly with uniform contact pressure at a macroscopic view, but at a microscopic view, the surface roughness will lead to non-perfect contact and non-uniform contact stress. By assuming that surface roughness has self-affined property, [45][46][47][48] this model can calculate the real contact area at every length scale. Thus, it is important to define the length scales for the battery systems.…”

Section: After LImentioning

confidence: 99%

“…The different length scale is described by wavenumbers, and the surface power spectrum density will have an exponential relationship with the wavenumber, proving the self-affine property. [45][46][47][48] Therefore, Persson's contact mechanics theory, 49 which models the contact area variation from 0% to 100% as a function of applied pressure on interfaces with the multi-scale self-affine property, will be adopted for the current model.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Simulation of the Effect of Contact Area Loss in All-Solid-State Li-Ion Batteries

Tian

2017

J. Electrochem. Soc.

128

View full text Add to dashboard Cite

Maintaining the physical contact between the solid electrolyte and the electrode is important to improve the performance of all-solidstate batteries. Imperfect contact can be formed during cell fabrication and will be worsened due to cycling, resulting in degradation of the battery performance. In this paper, the effect of imperfect contact area was incorporated into a 1-D Newman battery model by assuming the current and Li concentration will be localized at the contacted area. Constant current discharging processes at different rates and contact areas were simulated for a film-type Li|LiPON|LiCoO 2 all-solid-state Li-ion battery. The capacity drop was correlated with the contact area loss. It was found at lower cutoff voltage, the correlation is almost linear with a slope of 1; while at a higher cutoff voltage, the dropping rate is slower. To establish the relationship between the applied pressure and the contact area, Persson's contact mechanics theory was applied, as it uses self-affined surfaces to simplify the multi-length scale contacts in all-solid-state batteries. The contact area and pressure were computed for both film-type and bulk-type all-solid-state Li-ion batteries. The model is then used to suggest how much pressures should be applied to recover the capacity drop due to contact area loss. Conventional Li-ion batteries usually include a liquid electrolyte, which facilitates Li-ions transport between cathode and anode. However, the applications of Li-ion batteries are still limited by the flammability and narrow electrochemical window of the liquid electrolytes. 1-3During the past decades, several solid electrolytes 4-9 with the ionic conductivity close to the liquid electrolyte have been developed, thus enabled the development of all-solid-state batteries. The benefits of all-solid-state batteries are high energy density, non-flammability, and the large electrochemical window (if the solid electrolyte form stable interphase layers on electrode surface). 10,11However, a major bottleneck for all-solid-state Li-ion batteries lies at the high interfacial resistance due to two main factors, chemical effect and physical contact. 3 The chemical effect refers to the chemical changes at the solid-electrolyte/electrode interface that cause slower transport. The chemical changes include the interphase layer formation due to solid electrolyte decomposition, 11 and/or Li-ion depletion zone at the interface 12 (for example, LiPON/Li 2 CO 3 ). Physical contact induced impedance comes from the imperfect contact at the solid-electrolyte/electrode interface, which plays a more important role for batteries using solid-electrolytes than the conventional batteries employing liquid electrolytes. Liquid electrolytes can easily diffuse through the porous electrode and wet the electrode surface, so, any fracture and disconnection between solid particles will only cause electrical disconnection. However, for solid electrolytes, the fracture and disconnection will impede Li-ion transport, as well as electron transport. Thus...

show abstract

Power spectral density analysis and photoconducting behavior in copper(ii) phthalocyanine nanostructured thin films

Cited by 35 publications

References 60 publications

Orientation study of iron phthalocyanine (FePc) thin films deposited on silicon substrate investigated by atomic force microscopy and micro-Raman spectroscopy

Orientation study of iron phthalocyanine (FePc) thin films deposited on silicon substrate investigated by atomic force microscopy and micro-Raman spectroscopy

Orientation and electronic properties of phthalocyanines on polycrystalline substrates

Simulation of the Effect of Contact Area Loss in All-Solid-State Li-Ion Batteries

Contact Info

Product

Resources

About