Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics

Gravimetric sensors “Quartz Crystal Microbalance” (QCM)

QCM-D Applications Beyond QCM

J.-M Friedt

Conclusion

FEMTO-ST/Time & Frequency department [email protected] slides and references at jmfriedt.free.fr

January 24, 2018

1 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

Direct detection (bio)sensors • No sample preparation: continuous monitoring + time resolution (kinetic) • Surface immobilization of receptor molecules: multiple measurement steps are possible • Sensitivity defined by mass to physical measurement conversion efficiency • Selectivity defined by affinity of the surface functionalization to the targeted compound, rejecting unwanted interference (antibody) • Improved signal to noise ratio by using evanescent wave (rejects bulk noise and keep only close-to-surface signal) • Detection limit determined by system noise level (detection limit=noise/sensitivity) = complete system (electronics, fluidics ...) detection layer (organic, bio) organic interface (metallic interface) inorganic transducer (glass, quartz) 2 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

Quartz crystal resonator basics Examples of direction detection sensors: Surface Plasmon Resonance, (optical) waveguide sensors, vibrating cantilever, electrochemical enzyme sensors • Quartz crystal resonator: piezoelectric substrate confining an acoustic wave • Boundary conditions: half-wavelength confined between parallel A (plano-plano) or curved (plano-convex) sides of a quartz plate • Odd overtones are confined in the same boundary conditions • Resonance frequency determined by plate thickness and shear wave velocity: 3340 m/s in AT-cut quartz (temperature compensated) N=1, 3, 5 • Application: f = 5 MHz requires t = λ/2 = c/(2f ) = 334 µm

t

3 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

Quartz crystal resonator basics Examples of direction detection sensors: Surface Plasmon Resonance, (optical) waveguide sensors, vibrating cantilever, electrochemical enzyme sensors • Quartz crystal resonator: piezoelectric substrate confining an acoustic wave • Boundary conditions: half-wavelength confined between parallel (plano-plano) or curved (plano-convex) sides of a quartz plate • Odd overtones are confined in the same boundary conditions • Resonance frequency determined by plate thickness and shear wave velocity: 3340 m/s in AT-cut quartz (temperature compensated) • Application: f = 5 MHz requires t = λ/2 = c/(2f ) = 334 µm

4 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM)

Butterworth-Van Dyke electromechanical model

J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

• Butterworth-VanDyke model 1 2 3 : RLC series branch represents damped spring-mass (“motional branch”) • Electrodes separated by a dielectric define a parallel capacitance Mechanical M x¨ + hx˙ + kx = F h (damping) M (mass) k (stiffness) x (displacement) x˙ (velocity) √ Q = h1 kM q k ω0 = M

Electrical L1 q¨ + R1 q˙ + q/C1 = U R1 (resistance) L1 (inductance) 1/C1 (capacitance) q (electrical charge) i = dq/dt q (current) Q=

ω0 =

1 R

L C

R1 L1 C1

k C0 M h

√1 L1 C1

1 S. Butterworth, On electrically-maintained vibrations, Proc. Phys. Soc. (London), 27 410–424 (1914) 2 K.S. Van Dyke The electric network equivalent of a piezoelectric resonator, Phys. Rev 25 (6) 895 (1925) 3 D.W. Dye, The piezo-electric quartz resonator and its equivalent electrical circuit, Proc. Phys. Soc. (London) 38 (1) 399 (1925) 5 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM)

Butterworth-Van Dyke electromechanical model

J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

• Butterworth-VanDyke model 1 2 3 : RLC series branch represents damped spring-mass (“motional branch”) • Electrodes separated by a dielectric define a parallel capacitance Mechanical M x¨ + hx˙ + kx = F h (damping) M (mass) k (stiffness) x (displacement) x˙ (velocity) √ Q = h1 kM q k ω0 = M

Electrical L1 q¨ + R1 q˙ + q/C1 = U R1 (resistance) L1 (inductance) 1/C1 (capacitance) q (electrical charge) i = dq/dt q (current) Q=

L C

1 R

ω0 = √ 1

L1 C1

1 S.

Butterworth, On electrically-maintained vibrations, Proc. Phys. Soc. (London), 27 410–424 (1914) 2 K.S. Van Dyke The electric network equivalent of a piezoelectric resonator, Phys. Rev 25 (6) 895 (1925) 3 D.W. Dye, The piezo-electric quartz resonator and its equivalent electrical circuit, Proc. Phys. Soc. (London) 38 (1) 399 (1925) 6 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM)

Butterworth-Van Dyke electromechanical model

J.-M Friedt

• Butterworth-VanDyke model 1 2 3 : RLC series branch represents damped spring-mass (“motional branch”) • Electrodes separated by a dielectric define a parallel capacitance

Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

12/ 3/ 2016 8:45:34 AM 1311.6010K42- 103899- La

Trc1

Y11 Real 10 mS/ Ref 30 mS Cal Off

Mem4[Trc1]

Y11 Real 10 mS/ Ref 30 mS

0.08 0.07 0.06

C1 R1

M1

0.05

L1

C0

0.04 0.03 30 mS

1 M1 M2 M3 M1 M2 M3

9.996900 MHz 9.996562 MHz 9.997233 MHz 9.996900 MHz 9.996739 MHz 9.997069 MHz

20.081 mS 10.004 mS 10.005 mS 50.356 mS 19.987 mS 19.948 mS

M M 2 M 13

0.02

M2M3

0.01 0 -0.01 -0.02

Ch1 Start 9.99 MHz Trc3 250

Pwr -10 dBm Bw 100 Hz

Y11 Phase 50°/ Ref 0° Cal Off

Mem5[Trc3]

Stop 10.02 MHz

Y11 Phase 50°/ Ref 0°

2 M1 10.014586 MHz 29.84 °

200 150 100 50

Antiresonance: new concept introduced by the parallel capacitance

M1

0°0 -50 -100 -150 -200 -250

7 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

QCM sensitivity • QCM is claimed to detect “mass” bound to the sensor surface A • Definition of the sensitivity: S = dff · dm

4

dt

0

• Allows for comparing a wide range of acoustic transducers, from kHz to GHz and nanometric to macroscopic • Sauerbrey (1959) : df dλ df A df f 1 dt t = f = λ ⇒ S = f · Aρdt = f ρdf ·t = ρ·t

t

t: QCM thickness, ρ = 2.643 g.cm−3 : quartz density, dm = A · ρ · dt: adsorbed mass over area A Assumption: perturbation (dt  t) of a layer with same properties than quartz (ρL = ρ) Numerical application: 5 MHz QCM exhibits S = 11 cm2 /g 4 G. Sauerbrey, Verwendung von Schwingquarzen zur W¨ agung d¨ unner Schichten und zur Mikrow¨ agung, Zeitschrift f¨ ur Physik A Hadrons and Nuclei, 155 (2), 206–222 (1959) 8 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

Detection limit • • • • •

the smallest quantity that can be detected using the sensor e.g. 3σ with σ the measurement fluctuation (noise) includes all sources of noise: electronics, fluidics, digitization detection limit=noise/sensitivity long term drift=low noise correlated noise: baseline stabilization prior to running a measurement (double layer stabilization, temperature stabilization) • Typical resolution: 1 Hz at 5 MHz=0.2 ppm ⇒ dm = 18 ng/cm2 A • Protein film: ρprotein = 1.4 g/cm3 and 5 nm thick ⇒ 700 ng/cm2 • ⇒2.5% surface coverage by proteins can be detected with QCM

•

J.-M Friedt, K. H. Choi, L. Francis and A. Campitelli, Simultaneous Atomic Force Microscope and Quartz Crystal Microbalance measurements: interactions and displacement field of a QCM, Japanese J. Appl. Phys., 41 (6A), 2002, 3974-3977 9 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM)

Displacement and acceleration

J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

• F~ = m · ~a • static displacement: A0 = C × V = 2 pm/V since C = 1.4 · 10−12 m/V • dynamic displacement5 if Q = 1000 : A = A0 × Q = 2 nm/V • x = A sin(ωt) ⇒ v = A · ω(ωt) ⇒ |~a| ≤ A · ω 2 • f = 5 MHz: |a| = 2 · 10−9 × (2π × 5 · 106 ) = 2 · 106 m/s2

Excellent gravimetric sensitivity linked to the huge acceleration on the sensor surface

5 J.-M Friedt, K. H. Choi, L. Francis, A. Campitelli, Simultaneous Atomic Force Microscope and Quartz Crystal Microbalance measurements: interactions and displacement field of a QCM, Jap. J. of Appl. Phys. 41 (6A) pp.3974-3977 (2002) 10 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM)

Dissipation measurement (QCM-D)

J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

• Frequency related to “mass” (acoustic wave confinement boundary condition variation) • Dissipation = Q −1 related to viscous losses • Viscous losses related to the conformation of the molecules • B. Kasemo in G¨ oteborg: creation of Q-Sense 6

R. Richter & al, Pathways of Lipid Vesicle Deposition on Solid Surfaces: A Combined QCM-D and AFM Study, Bio. J. 85 3035–3047 (2003)

6 M.

Rodahl, F. H¨ o¨ ok, A. Krozer, P. Brzezinski, B. Kasemo, Quartz crystal microbalance setup for frequency and Qfactor measurements in gaseous and liquid environments, Rev. Sci. Instrum. 66 (7) 3924–3930 (1995)

11 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

Shear wave penetration depth • Newtonian fluid: constant stress-strain relation defines the viscosity • Fluids characterized by dynamic (shear) viscosity η: dragged by the shear wave • Exponentially decaying displacement 7 with depth (6= propagative pressure wave) q η • A(z) = A(0) exp(−z/δ) with δ = ρω • Considering the dynamic viscosity of water η = 1 cP, and ρ = 1 g.cm−3 , then r z 10−2 δ= cm = 180 nm 2π × 5 · 106

A vibrating surface

7 K.K Kanazawa & J.G. Gordon, The oscillation frequency of a quartz resonator in 12 / 28 contact with liquid, Analytica Chimica Acta 175 99–105 (1985)

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics

Measurement examples: electrochemical deposition • Reversible thin film deposition controlled electrically • Examples: Cu ↔ Cu 2+ + 2e − or Ag ↔ Ag + + e −

QCM-D Applications Beyond QCM Conclusion

Ag

Cu Rigid layer ⇒ ∆fn /n ∝ √ ∆mlayer (low damping) Viscous layer ⇒ ∆fn / n ∝ {∆mliquid , ∆mlayer } (high damping)

13 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D

Measurement examples: globular proteins surface chemistry: hydrophobic thiol on gold

• • S-layer protein forms a crystal on a hydrophobic surface (reversible) • little/no variation of the quality factory (damping) • simultaneous optical measurement: thickness and density of the layer

Applications Beyond QCM Conclusion

Globular proteins ∼ thin rigid film: valid approximations for both acoustic (mass effect) and optics ⇒ conditions applied during BIAcore’s radiolabelling calibration 8 8 J.-M Friedt, L. Francis, G. Reekmans, R. De Palma, A. Campitelli and U.B. Sleytr, Simultaneous surface acoustic wave and surface plasmon resonance measurements: electrodeposition and biological interactions monitoring, J. of Appl. 14 / 28 Phys., 95 (4), 2004, 1677-1680

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM

•

Measurement examples: fibrillar Globular proteins (S-layer, IgG, IgE, BSA ...) proteins

are short and spread on the surface (5-10 nm) as a rigid layer • Fibrillar proteins (collagen, fibrinogen) extend deep in the buffer solution, equivalent to a thick layer full of solvent ⇒ strong contribution of viscosity

Conclusion

• rigid interaction: ∆fN ∝ N • viscous √ interaction: ∆fN ∝ N • Large damping variation and √ ∆fN /N scaling as N as opposed to constant: signatures of viscous interactions 30 µg/ml collagen 15 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction

Measurement conclusions ⇒ optics underestimates the adsorbed mass (lower optical index than expected)

QCM basics QCM-D Applications Beyond QCM Conclusion

Analyte (bulk concentration, µg/ml)

collagen (30µg/ml) collagen (300µg/ml) fibrinogen (46µg/ml) fibrinogen (460µg/ml)

√ ∆fn / n (Hz) QCM

2 − 12

?

?-1000

NO

50

4.7 ± 0.7 1.0 ± 0.1

75 ± 15 100

NO NO

45=900 8=160

3-5 0.2-0.5

± ± ± ±

1000 1200 110±5 NO

NO NO 55±5' 1110 100=1700

100 >120 4-10 8-10

d (nm) SAW/SPR

560±20 135±15 1750±150 2100±200 750±100 1500±500

16.0 ± 3.0 19.0 ± 3.0 6.0 ± 1.5 13.0 ± 2.0

25 35 50 50

Cu S-layer CTAB

x (%) SAW/SPR

surface density (ng/cm2 )

15 10 10 10

∆fn /n (Hz) QCM

∆D (×10−6 ) QCM

16 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction

Measurement conclusions ⇒ acoustics overestimates the adsorbed mass (bound solvent to the organic layer)

QCM basics QCM-D Applications Beyond QCM Conclusion

Analyte (bulk concentration, µg/ml)

collagen (30µg/ml) collagen (300µg/ml) fibrinogen (46µg/ml) fibrinogen (460µg/ml)

√ ∆fn / n (Hz) QCM

2 − 12

?

?-1000

NO

50

4.7 ± 0.7 1.0 ± 0.1

75 ± 15 100

NO NO

45=900 8=160

3-5 0.2-0.5

± ± ± ±

1000 1200 110±5 NO

NO NO 55±5' 1110 100=1700

100 >120 4-10 8-10

d (nm) SAW/SPR

560±20 135±15 1750±150 2100±200 750±100 1500±500

16.0 ± 3.0 19.0 ± 3.0 6.0 ± 1.5 13.0 ± 2.0

25 35 50 50

Cu S-layer CTAB

x (%) SAW/SPR

surface density (ng/cm2 )

15 10 10 10

∆fn /n (Hz) QCM

∆D (×10−6 ) QCM

17 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction

Sensitivity mapping & packaging Scanning Electrochemical Microscope mapping of a QCM gravimetric sensitivity 9

QCM basics QCM-D Applications Beyond QCM Conclusion

• strongest sensitivity at center of electrode • sensitivity vanishes on the surrounding of the resonator • the higher the overtone, the better the energy confinement over the electrode • O-ring around the sensor will not impact the acoustic wave

9 A.C. Hillier & M.D Ward, Scanning electrochemical mass sensitivity mapping of the quartz crystal microbalance in liquid media, Anal. Chem. 64 (21) 2539–2554 (1992) 18 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt

Beyond the bulk acoustic resonator: FBAR

Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

A 1 dm • S = dff · dm = ρ·t ⇒ dff = ρ·A·t = dm m with m the mass of the resonator • increasing S requires shrinking m and hence t • thin Film Bulk Acoustic Resonator: replace bulk acoustic resonator with piezoelectric film on a membrane • but rising S associated with rising f0 ...

• ... and oscillator noise rises with f0 , degrading the detection limit • ⇒ is the detection limit improved on a FBAR architecture ?

Challenge of generating shear wave on a thin piezoelectric film deposited using a vaport method (C-axis normal to the growth plane)

19 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt

Beyond the bulk acoustic resonator: SAW

Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

• Another strategy for reducing the mass of the vibrating element: confine the acoustic wave to the surface • SAW: Surface Acoustic Wave devices • Rayleigh wave boundary conditions only met at the free surface ... • ... but Rayleigh waves exhibit out-of-plane component radiating as pressure waves in fluids. • Shear wave can be confined on a surface if a slow guiding layer is deposited on the surface (cf optical fiber) • Love-mode SAW devices exhibit high sensitivity and compatibility with liquid media • Love mode SAW sensors extensively used as bio-sensors. Example: N-isopropyl acrylamide (N-IPAAM) is a polymer whose conformation (hydrophilic v.s hydrophobic) changes with temperature 20 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

Beyond the bulk acoustic resonator: SAW • Another strategy for reducing the mass of the vibrating element: confine the acoustic wave to the surface • SAW: Surface Acoustic Wave devices • Rayleigh wave boundary conditions only met at the free surface ... • ... but Rayleigh waves exhibit out-of-plane component radiating as pressure waves in fluids. • Shear wave can be confined on a surface if a slow guiding layer is deposited on the surface (cf optical fiber) • Love-mode SAW devices exhibit high sensitivity and compatibility with liquid media • Love mode SAW sensors extensively used as bio-sensors. Example: N-isopropyl acrylamide (N-IPAAM) is a polymer whose conformation (hydrophilic v.s hydrophobic) changes with temperature 21 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics

Measurement example • From SAW: phase and magnitude measurements • From SPR: optical thickness → exploit the viscous dissipation of the propagating acoustic wave −21

Applications

NIPAAM (N-isopropyl acrylamide) Thermocouple 1 0 0 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 1 0 0 1 1 0 1 0 0 1 0 1 0 1 0 1

z

Input IDT 101100 x

1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1

Guiding layers Piezoelectric substrate Coupling prism

LASER 670 nm

Notice this is very difficult to reproduce with QCM (bottom side of sensor in contact with prism)

−21.5 −22 −22.5 −23 20

Liquid cell Output IDT

SAWΔ φ (◦ )

Conclusion

SPR Δ θ (m◦ )

Beyond QCM

SAW A (dB)

QCM-D

25

30

35

40

45

−30 20

25

30

35

40

45

1200 1000 800 600 400 200 0 −200 20

25

30

35

40

45

0 −10 −20

Temperature (◦ C)

22 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics

Measurement example • From SAW: phase and magnitude measurements • From SPR: optical thickness → exploit the viscous dissipation of the propagating acoustic wave

QCM-D

6

Cycle 1 (22.4 °C − 39.1 °C − 22.9 °C)

1200

6

Cycle 2 (22.9 °C − 41.2 °C − 23.9 °C)

1200

15

6

38.9

34.7

28.2

Cycle 3 (23.9 °C − 40.4 °C − 23.5 °C)

0 22.9

900

4

600

3

300

2 23.9

32.5

39.6

35.2

28.8

0 23.5

°

300

2 22.9

1200

5

3

6

31.2

41

36.2

29.4

Cycle 4 (23.5 °C − 43.4 °C − 26.1 °C)

0 23.9

900

4

600

3

300

90

2

34.9 °C ↓

681

501

5

° 30.8 C ↓ 146

25 °C

0

1200

5

PNIPAAm layer content (%)

30.5

600

20

146

25

30

35

40

45

Layer thickness (nm)

50

55

60

4

34.9 °C ↓

2 23.5

34

42.8

38.8

31.7

0 26.1

L. Francis, J.-M. Friedt, C. Zhou, P. Bertrand In situ evaluation of density, viscosity and thickness of adsorbed soft layers by combined surface acoustic wave and surface plasmon resonance, Anal. Chem. 2006; 78 (12) (2006), pp. 4200-4209

3.5

3

Viscosity (cP)

2 22.4

SPR Δθ (m )

300

4

10

°

3

35.1 °C ↑

900

SPR Δθ (m )

600

5

1

4

SPR Δθ (m°) SAW ΔA/Δφ (dB/rad)

900

SPR Δθ (m°) SAW ΔA/Δφ (dB/rad)

5

50

Conclusion

SAW ΔA/Δφ (dB/rad)

Beyond QCM

SAW ΔA/Δφ (dB/rad)

Applications

2.5

35.1 °C ↑

2

30.8 °C ↓

1.5

1 20

25 °C 25

30

35

40

45

Layer thickness (nm)

50

55

60

23 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

Device characterization • Typical frequency: 150 MHz • Acoustic wave velocity: shear wave on quartz 5060 m/s • λ = c/f = 33 µm • two-electrodes separated by a 50% gap: 8 µm-wide electodes • fluidic confinement challenge: water over the electrodes induces a capacitive short circuit ⇒ wall with wavelength width over the acoustic path to confine the liquid

24 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM)

QCM basics QCM-D Applications Beyond QCM Conclusion

10

• Two approaches: oscillator and frequency counter (closed loop), or frequency sweep and phase/magnitude measurement (open loop)

• ϕ = 2π · f · τ = 2π · f · D/v ⇒ (D: distance between IDTs)

dϕ df

= 2π Dv

• observe ϕ at fixed frequency and variations of v induces variation τ and hence ϕ

1 2 3 4

-30 -35 -40 -45 -50 -55

• Oscillator Barkhausen conditions are difficult to meet in strongy varying environments (losses) • Network analyzer will always provide some characteristics, if only of a failing sensor

device device device device

-25 Amplitude (dB)

Introduction

• Detection limit determined by sensitivity and reader electronics noise

152

154 156 158 Frequency (MHz)

200

160

device device device device

150 Phase (degree)

J.-M Friedt

Electronics

-20

100

1 2 3 4

50 0 -50

-100 -150 -200

154

156 158 Frequency (MHz)

160

10 D. Rabus, J.-M. Friedt & al., A high sensitivity open loop electronics for gravimetric acoustic wave-based sensors, IEEE Trans. UFFC 60 (6), 1219–1226 (2013)

25 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

Electronics

10

• Detection limit determined by sensitivity and reader electronics noise • Two approaches: oscillator and frequency counter (closed loop), or frequency sweep and phase/magnitude measurement (open loop)

Magnitude Phase

AD9954

• ϕ = 2π · f · τ = 2π · f · D/v ⇒ (D: distance between IDTs)

dϕ df

1 0 0 1

AD8367

Gain controller

SYPD−2

Magnitude Phase

AD9954

Source

• Oscillator Barkhausen conditions are difficult to meet in strongy varying environments (losses) • Network analyzer will always provide some characteristics, if only of a failing sensor

ADuC7026 A A D Controller D C C SPI

SAW sensors

AD8367

phase detector

SYPD−2

low noise amplifier

low noise amplifier

1 0 0 1

= 2π Dv

• observe ϕ at fixed frequency and variations of v induces variation τ and hence ϕ

10 D. Rabus, J.-M. Friedt & al., A high sensitivity open loop electronics for gravimetric acoustic wave-based sensors, IEEE Trans. UFFC 60 (6), 1219–1226 (2013) 26 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction

Ongoing project Replace passive glass slides in optical systems with active SAW transducers 11

QCM basics QCM-D Applications Beyond QCM Conclusion

Replace the low permittivity quartz with high permittivity, strongly coupled lithium tantalate ⇒ solve the fluidic handling by solving the capacitive short circuit issue ? 11 J.-M Friedt, L. Francis, Combined surface acoustic wave and surface plasmon resonance measurement of collagen and fibrinogen layers, Sensing and Bio-sensing Research, 2016 27 / 28

Gravimetric sensors “Quartz Crystal Microbalance” (QCM) J.-M Friedt Introduction QCM basics QCM-D Applications Beyond QCM Conclusion

Conclusion • The quartz crystal resonator: much more than a “microbalance” • direct detection system for probing thin film properties, including mass (density× thickness) and viscosity • Readily accessible substrates (cf. electronics quartz resonators) for experimenting • Opportunity to use radiofrequency electronics design skills • Ability to measure sub-100 ng.cm−2 masses: even used on satellites to assess outgassing 12 13 ! TODO • Experiment by yourself14 : jmfriedt.free.fr/QCM_BUP.pdf • Prepare the lab session: jmfriedt.free.fr/tp_tuningfork.pdf 12 R. Naumann, W. Moore, D. Nisen, W. Russell & P. Tashbar, Quartz crystal microbalance contamination monitors on Skylab: A quick look analysis (1973) 13 B.E. Wood & al., Review of Midcourse Space Experiment (MSX) satellite quartz crystal microbalance contamination results after 7 years in space, Proc. 9th Intl Symp. on Materials in a Space Environment (2003) 14 J.-M. Friedt, Introduction ` a la microbalance ` a quartz : aspects th´ eoriques et exp´ erimentaux, Bulletin de l’Union des Physiciens n.852 (March 2003), pp.429-440 28 / 28