LOGIN TO YOUR ACCOUNT

Username
Password
Remember Me
Or use your Academic/Social account:

CREATE AN ACCOUNT

Or use your Academic/Social account:

Congratulations!

You have just completed your registration at OpenAire.

Before you can login to the site, you will need to activate your account. An e-mail will be sent to you with the proper instructions.

Important!

Please note that this site is currently undergoing Beta testing.
Any new content you create is not guaranteed to be present to the final version of the site upon release.

Thank you for your patience,
OpenAire Dev Team.

Close This Message

CREATE AN ACCOUNT

Name:
Username:
Password:
Verify Password:
E-mail:
Verify E-mail:
*All Fields Are Required.
Please Verify You Are Human:
fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Bailey, James (2014)
Languages: English
Types: Unknown
Subjects:
Polymer distributed Bragg reflectors (DBRs) were prepared by spin-casting alternating layers of polystyrene (PS) and poly(vinylpyrrolidone) (PVP) from mutually exclusive (orthogonal) solvents. These all polymer photonic structures were prepared using a purpose built automated spin-coater system. Samples were prepared with targeted optical properties such as the wavelength position, intensity and bandwidth of reflection peaks. The wavelength position of the reflection peaks was controlled by the deposition spin-speed used during sample preparation. Reflectance was controlled by the number of layers deposited onto the sample. The bandwidth was increased by chirping the layers in the photonic structure. Reflection bands were measured in the UV/visible region of the spectrum using two different (transmission and reflection mode) purpose built spectrometer set-ups. Measured reflection bands had narrow bandwidths between 10nm and 20nm. Chirping these photonic structures broadened the peaks to bandwidths of ~ 50nm. A 100 layer PVP/PS DBR had a total reflectance of 93 ± 1%. The wavelength of the reflection peaks from flat DBR samples blue-shifted when measured away from normal incidence. This was reduced when corrugating a DBR by wrinkling the films with mechanical strain. The wavelength of the reflection band from a corrugated DBR remained constant when the sample was rotated. Thus improving the angular dependence of the structures. Fourier transform infra-red spectroscopy was used to measure reflection bands which were between wavelengths of 1600 nm and 2700 nm. These reflection bands had narrow bandwidths between 40 nm and 60 nm. The largest reflectance measured within the infra-red spectra was 80 ± 1% from a 50 layer PVP/PS DBR. A modified optical transfer matrix method was used to model the optical properties of the DBRs. Changes in the refractive index contrast (between 0.020 and 0.028 for 30 layer PVP/PS DBRs) were needed to fit the model to the measured UV/visible spectra. It was concluded that trapped solvent (from sample preparation) was lowering the refractive indices of the layers. The polymer-polymer interface widths of spin-cast polymer multi-layers were measured using neutron reflectivity. Each polymer-polymer interface width was less than 1nm throughout the DBR samples. The polymer multi-layer samples were measured using time of flight secondary ion mass spectrometry (TOF-SIMS). An Ar2000+ sputtering source was used to etch through the multi-layer samples. It was concluded that the thickness of spin-cast films did not change when preparing a multi-layer structure. However, other techniques, such as ellipsometry, are more suitable for measuring the thickness of films. The TOF-SIMS technique was unable to measure polymer-polymer interface widths in multi-layer samples. This was due to the sputtering beam roughening/mixing the polymers at the interfaces. It was concluded that PVP/PS DBRs could be used as inexpensive narrowband reflectors/filters. However, alternative polymer systems may be more useful for other applications which require a greater reflectance. This includes creating resonant cavities to improve the efficiency of optical devices (such as LEDS and solar cells). The results and techniques from these experiments are useful for further development in polymer photonic structures and polymer multi-layer devices.
  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • 1. James Bailey and James S. Sharp, \Thin Film Polymer Photonics: Spin Cast Distributed Bragg Re ectors and Chirped Polymer Structures", European Physical Journal E, 33:41-49, 2010.
    • 2. James Bailey and James S. Sharp, \Infrared Dielectric Mirrors Based on Thin Film Multilayers of Polystyrene and Polyvinylpyrrolidone", Journal of Polymer Science Part B: Polymer Physics, 49:732-739, 2011.
    • 3. Rasmus Havelund, Antonino Licciardello, James Bailey, Nunzio Tuccitto, Davide Sapuppo, Ian S Gilmore, James S Sharp, Joanna LS Lee, Taou q Mouhib and A Delcorte, \Improving secondary ion mass spectrometry C60n+ sputter depth pro ling of challenging polymers with nitric oxide gas dosing", American Chemical Society", vol.85, no.10, 5064-5070, 2013.
    • 2 Literature review 13 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.2 Structural colour and Bragg re ection . . . . . . . . . . . . . . . 13 2.3 Structural colour in nature . . . . . . . . . . . . . . . . . . . . . 19 2.4 Man-made photonic structures . . . . . . . . . . . . . . . . . . . 21 2.5 Optical devices which make use of photonic structure . . . . . . 23 2.6 Polymer multi-layer devices . . . . . . . . . . . . . . . . . . . . 25
    • 3 The physics of re ection from lms and multi-layers 27 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.2 Fresnel re ection and transmission coe cients . . . . . . . . . . 27 3.3 Boundary matrix . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3.4 Transmission matrix . . . . . . . . . . . . . . . . . . . . . . . . 33 3.5 The optical matrix method . . . . . . . . . . . . . . . . . . . . . 35 3.6 Application to multi-layers . . . . . . . . . . . . . . . . . . . . . 37 3.7 Modelling di use interfaces . . . . . . . . . . . . . . . . . . . . . 39 3.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
    • 4 Experimental techniques 41 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4.2 Spin-coating thin lms . . . . . . . . . . . . . . . . . . . . . . . 41 4.2.1 Polymer and solvent selection . . . . . . . . . . . . . . . 43 4.3 Multi-layer sample preparation . . . . . . . . . . . . . . . . . . 47 4.3.1 Automated sample preparation . . . . . . . . . . . . . . 49 4.3.2 Multi-layer lm thickness . . . . . . . . . . . . . . . . . . 53 4.3.3 Annealing DBR samples . . . . . . . . . . . . . . . . . . 53
    • 6 Improving the preparation and re ectance of PVP/PS DBRs133 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 6.2 DBR samples after ageing . . . . . . . . . . . . . . . . . . . . . 133 6.3 Asymmetry and symmetry of lm thickness . . . . . . . . . . . 139 6.4 Periodically annealing during sample preparation . . . . . . . . 144 6.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
    • 7 Infra-red measurements and properties of polymer DBRs 148 7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 7.2 Measuring the e ects of HCl swelling . . . . . . . . . . . . . . . 149
    • 9 Using polymer multi-layers to calibrate TOF-SIMS experiments177 9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 9.2 Bi-layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 9.3 Asymmetric multi-layers . . . . . . . . . . . . . . . . . . . . . . 184 9.3.1 Non-chirped samples . . . . . . . . . . . . . . . . . . . . 186 9.3.2 Chirped . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 9.4 Multi-layers of thicker lms . . . . . . . . . . . . . . . . . . . . 195 9.5 Analysis of errors in TOF-SIMS measurements . . . . . . . . . . 199 9.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
    • 10 Improving the angular dependence by corrugating DBR lms201 10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 10.2 Optical properties of curved DBRs . . . . . . . . . . . . . . . . 202 10.3 Corrugating thin lms . . . . . . . . . . . . . . . . . . . . . . . 204 10.3.1 Preparing the elastomer substrate . . . . . . . . . . . . . 205 10.3.2 Preparing the CA/PVK DBR . . . . . . . . . . . . . . . 205 10.3.3 Corrugating the CA/PVK DBR . . . . . . . . . . . . . . 211 10.4 Physical properties of the corrugated DBR . . . . . . . . . . . . 211 10.5 UV/visible properties of corrugated DBRs . . . . . . . . . . . . 214 10.5.1 Specular re ection measurements . . . . . . . . . . . . . 215 10.5.2 Changing measured angle of re ection r . . . . . . . . . 218
    • [1] Mitsuteru Kimura et. al. Tunable multilayer- lm distributed-braggre ector lter. Journal of Applied Physics, 50(3):1222{1225, 1976.
    • [2] Richard Lytel et. al. Narrowband electrooptic tunable notch lter. Applied Optics, 25(21):3889{3895, 1986.
    • [3] V. Mullonia et. al. Porous silicon microcavities as optical chemical sensors. Applied Physics Letters, 76(18):2523, 2525 2000.
    • [12] S Kinoshita et. al. Physics of structural colors. Rep. Prog. Phys., (71), 2008.
    • [25] Basudam Adhikari et. al. Polymers in sensor applications. Progress in Polymer Science, 29:699{766, 2004.
    • [26] Jeroen K. J. van Duren et. al. Relating the morphology of poly(pphenylene vinylene)/mathanofullerene blends of solar-cell performance. Advanced Functional Materials, 14(5):425{434, 2004.
    • [50] David Voss. Cheap and cheerful circuits. Nature, 407:442{444, Sept 2000.
    • [51] R.M.A. Azzam and N.M. Bashara. Ellipsometry and polarized light. Elsevier Science, 3rd edition, 1996.
    • [52] Charalambos C. Katsidis et. al. General transfer-matrix method for optical multilayer systems with coherent, partially coherent, and incoherent interference. Applied Optics, 41(19):3978{3987, 2002.
    • [53] Klaus Halbach. Matrix representation of gaussian optics. American Journal of Physics, 32(90), 1964.
    • [109] David J. Farmer et. al. Quantized phonon modes in loaded polymer lms. Journal of applied physics, 113(033516), 2013.
  • Inferred research data

    The results below are discovered through our pilot algorithms. Let us know how we are doing!

    Title Trust
    49
    49%
  • No similar publications.

Share - Bookmark

Cite this article