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Project results :

Patent:

 • Procedeu de depunere a filmelor nanocompozite (nanoparticule/polimer) pentru senzori cu unde acustice de suprafata , C. Viespe , I. Nicolae, C. Grigoriu, A/00743/19-10-2012.

ISI Articles:

 • Investigation of a polymeric nanostructured sensing layer deposited by MAPLE direct write, I. Nicolae, C. Viespe, N. Serban, C. C. Negrila, V. S. Teodorescu, L. Trupina, sent to be published at Sensors & Actuators: B. Chemical, Manuscript Number: SNB-D-13-00832 (2013).

 • SAW Sensor Based on Highly Sensitive Nanoporous Palladium Thin Film for Hydrogen Detection, C. Viespe, C. Grigoriu, Microelectronic Engineering, vol. 108, 218-221, (2013).

• Design of a surface acoustic wave sensors array, H. Pais, C. Grigoriu, C. Viespe , Optoelectron Adv Mat , Vol. 6, No. 11-12, 1085-1088, (2012).

•  Nanocomposite sensitive polymeric films for SAW sensors deposited by the MAPLE direct write technique, I. Nicolae, C. Viespe, C. Grigoriu, Sens. Actuators B-Chem. 158, 418-422, (NOV 15 2011).

Other Articles:

Sensor array able to detect and recognise chemical warfare agents, I. Bucur, S. Serban, A. Surpateanu, N. Cupcea, C. Viespe, C. Grigoriu, C. Toader, N. Grigoriu, JISOM, ISSN 1843-4711, vol. 5, no. 2, 256-263, DEC 2011

Conference presentation:

Comparativ Study of Surface Acoustic Wave Sensors Coated with Nanoporous Films for Hydrogen Detection, C. Viespe, C. Grigoriu, 3rd International Conference on Materials and Aplications for Sensors and Transducers, 13-17 septembrie 2013, Praga – Cehia – prezentare orala

Surface acoustic wave hydrogen sensor based on Pd nanoporous films imprinted with waveguide channels, C. Viespe, I. Nicolae, C. Grigoriu, 10th International Conference on Nanosciences & Nanotechnologies, 9-12 July 2013, Thessaloniki, Grecia –oral presentation.

•  Surface acoustic wave sensors coated with nanoporous ZnO film for hydrogen detection, C. Viespe, C. Grigoriu, 3 th Intenational Conference of Modern Laser Aplications, 20-24 May 2013, Bran, Romania - oral presentation.

• Highly sensitive nanoporous palladium thin films SAW sensor for hydrogen detection, C. Viespe, C. Grigoriu, 6 th International Meeting on Developments in Materials, Processes and Applications of Emerging Technologies, 2-4 July 2012, Alvor, Portugalia oral presentation.

•  Comparative Study of Surface Acoustic Wave Sensors Coated with Pd and ZnO for Hydrogen Detection at Room Temperature , C. Viespe, C. Grigoriu, R. Barjega, ATOM-N2012, August 23th 26th, 2012, Constanta, Romania oral presentation.

•  Surface acoustic wave sensors coated with nanocomposite (polymer/nanoparticles) sensitive layers deposited by combined laser/spray technique, C. Viespe, I. Nicolae, C. Grigoriu, T. Lucian, E-MRS 2012 FALL MEETING, September 17-21 2012, Warsaw University of Technology, Polonia.

•  Surface Acoustic Wave Sensors for Hydrogen Detection based on Pd and ZnO Nanoporous Layers Deposited by a ps Laser Technique, C. Viespe, C. Grigoriu, ROMOPTO 2012, 3-6 September 2012, Bucuresti, Romania.

•  Surface Acoustic Wave Sensors based on Nanoporous Films for Hydrogen Detection, C. Viespe, C. Grigoriu, 9th International Conference on Physics of Advanced Materials 20 - 23 September 2012, Iasi, Romania.

Summary results of the project:

  • It was deposited nanoporous films of WO3, Pd, ZnO at different experimental conditions:

-  laser wavelengths : 355 nm, 532 nm, 1064 nm
-  power densities: 150 MW/cm2; 180 MW/cm2; 250 MW/cm2
-  oxygen/inert gas pressures: 50 mTorr; 150 mTorr; 300 mTorr

  • It was characterized the nanoporous films of WO3, Pd, ZnO (morphology, thickness)


XRD patterns of the ZnO, Pd and WO3 film samples (gas pressure 300 mTorr, power density 160 MW/cm2, repetition rate 50 kHz, deposition time 2 h).

SEM images of Pd, ZnO, and WO3 the surface layer (gas pressure 300 mTorr, power density 160 MW/cm2, repetition rate 50 kHz, deposition time 2 h).



Sensitive layer of Pd (300 mTorr, 160 MW/cm2): (a) nanoparticle size distribution and (b) cross section SEM image.

Between nanoporous films of Pd, ZnO, and WO3, the best sensitivity and limit of detection was achievement  by the sensors based on Pd films.
The sensitivity and detection limit at RT were 0.31 Hz/ppm and 48 ppm, respectively, for sensors based on films deposited at 300 mTorr, 160 MW/cm2, and 50 kHz for 2 h. These results indicated that high sensitivities can be achieved utilising a nanoporous layer structure for gas sensing applications.

It was designed and imprinted waveguide channels and investigated their influence on SAW sensors.


Experimental setup used to mark the waveguide channels.

Photo of SAW sensors, cut in a parallelogram geometry and imprinted with waveguide channels.

  • It was studied the hydrogen detection performance of SAWS based on channelled nanoporous sensitive layers


Frequency shift for Pd nanoporous films toward 0.015-2% hydrogen concentration at RT  (300 mTorr, 160 MW/cm2)

Dynamic response of palladium layer-based SAWS with/without channels for H2 gas at RT.

Sensitive layer

Sensitivity (Hz/ppm)

Limit of detection
(ppm)

Noise
(Hz)

Pd with waveguids

0.32

20

2

Pd without waveguids

0.38

34

4

ZnO without waveguids

0.03

313

3

WO3 without waveguids

0.02

530

4

Sensitivity              - frequency shift per analyte concentration [Hz/ppm].
Limit of detection   - 3 × noise level (5 Hz) per sensitivity [ppm].

   
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