MOLECULAR EMITTERS AS A TUNABLE LIGHT SOURCE FOR OPTICAL MULTISENSOR SYSTEMS

(1)

A n a s t a s i i a S u r k o v a

^{1 , 2}

, A l e k s a n d r a P a d e r i n a

¹

, A n d r e y L e g i n

¹

, E l e n a G r a c h o v a

¹

, D m i t r y K i r s a n o v

¹

MOLECULAR EMITTERS AS A TUNABLE LIGHT SOURCE FOR OPTICAL

MULTISENSOR SYSTEMS

1 Institute of Chemistry, St. Petersburg State University, St. Petersburg, Russia

2 Samara State Technical University, Samara, Russia

(2)

OPTICAL MULTISENSOR SYSTEM (OMS)

• Multisensor system – an analytical device

• composed of two or more sensors

• optimized for a particular analytical task

• employs chemometrics to maintain accuracy

• Advantages

• inexpensive

• portable

• on-site/on-line implementation

• OMS composed of

• light sources

• photodetectors

• optical fibers

• 3D-printed parts, etc.

Example of OMS

^a

(3)

PURPOSE OF THIS STUDY

• To develop OMS prototype based on

molecular emitters as a tunable light source

• To study a real-life applicability of the

developed prototype

(4)

MOLECULAR EMITTERS AS A LIGHT SOURCE

• Properties

• laser diode excites the emission of molecular emitters

• Requirements to choose emitters

• absorption spectrum must not overlap with emission spectrum

• excitation radiation must fit into the absorption maximum

• brightness (quantum yield of emission)

• emission wavelength in solid phase

• Advantages

• high versatility

• short analysis time

• adjustment of the emission wavelength for a specific application

(5)

EXAMPLES OF MOLECULAR EMITTERS

Ir( III ) compl e xe s Cu( I) com pl exe s

_[Cu(MePPy₃_)I]₂_[Cu₂_I₄_{] (1)}

[Cu₄I₄(py)₄] (2) [Cu(Tpdp)I] (3)

[CuCl(PPh₃)₂(py)] (4) [Cu(PPh₃)₃(4-Mepy)]Br (5) [CuI(PPh₃)₂(4-Mepy)] (6) [Ir(dfppy)₂(bpbpy)]PF₆ (1)

[Ir(ppy)₂(bpbpy)]PF₆ (2) [Ir(pybt)₂(bpbpy)]PF₆ (3) [Ir(mpqc)₂(bpbpy)]PF₆ (4)

(6)

MOLECULAR EMITTERS AS A LIGHT SOURCE

Ir( III ) compl e xe s Cu( I) com pl exe s

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

normalized emission

wavelength (nm)

Ir(III) complexes

normalized emission

wavelength (nm)

Cu(I) complexes

Emission spectra of the mixtures

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

normalized emission

wavelength (nm)

Ir(III) complexes

normalized emission

wavelength (nm)

Cu(I) complexes

(7)

EXPERIMENTAL

(1) (2)

(1) Ir(III)-based OMS ^a (2) Cu(I)-based OMS

Sample volume 0.15 mL 4 mL

Sample placement glass cup (1 cm in diameter) polystyrene Petri dish (3.5 cm in diameter) Excitation source laser diode (λ_exct = 365 nm) laser diode (λ_exct = 385 nm) /

UV flashlight (λ_exct = 365 nm) Detector fiber-optic UV−vis spectrometer AvaSpec-ULS2048CL-EVO

(8)

RESULTS FOR MODEL SOLUTIONS

Ir( III )- bas ed OM S Cu( I)- ba se d OM S

0.00 0.02 0.04 0.06 0.08 0.10

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

0.00 0.02 0.04 0.06 0.08 0.10

calibration validation

Co predicted

Co measured

Cu predicted

Cu measured

a.u.

wavelength, nm

Co, 1st loading Co, spectrum

a.u.

wavelength, nm

Cu, 1st loading Cu, spectrum

RMSECV = 0,005/0.04 ^b R² = 0.98/0.99 ^b LV = 2 RMSECV = 0.009 ^a

R² = 0.94 ^a LV = 2

Co predicted

Co measured

RMSECV = 0.013/0.004 ^b R² = 0.84/0.98 ^b LV = 2

Cu predicted

Cu measured RMSECV = 0.003 ^a R² = 0.99^a LV = 2

0.00 0.02 0.04 0.06 0.08 0.10

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

0.00 0.02 0.04 0.06 0.08 0.10

Co predicted

Co measured

Cu predicted

Cu measured

a.u.

wavelength, nm

a.u.

wavelength, nm

R² = 0.94 ^a LV = 2

Co predicted

Co measured

RMSECV = 0.013/0.004 ^b R² = 0.84/0.98 ^b LV = 2

Cu predicted

0.00 0.02 0.04 0.06 0.08 0.10

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

0.00 0.02 0.04 0.06 0.08 0.10

Co predicted

Co measured

Cu predicted

Cu measured

a.u.

wavelength, nm

a.u.

wavelength, nm

R² = 0.94 ^a LV = 2

Co predicted

Co measured

RMSECV = 0.013/0.004 ^b R² = 0.84/0.98 ^b LV = 2

Cu predicted

0.00 0.02 0.04 0.06 0.08 0.10

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

0.00 0.02 0.04 0.06 0.08 0.10

Co predicted

Co measured

Cu predicted

Cu measured

a.u.

wavelength, nm

a.u.

wavelength, nm

R² = 0.94 ^a LV = 2

Co predicted

Co measured

RMSECV = 0.013/0.004 ^b R² = 0.84/0.98 ^b LV = 2

Cu predicted

0.00 0.02 0.04 0.06 0.08 0.10

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

0.00 0.02 0.04 0.06 0.08 0.10

Co predicted

Co measured

Cu predicted

Cu measured

a.u.

wavelength, nm

a.u.

wavelength, nm

R² = 0.94 ^a LV = 2

Co predicted

Co measured

RMSECV = 0.013/0.004 ^b R² = 0.84/0.98 ^b LV = 2

Cu predicted

0.00 0.02 0.04 0.06 0.08 0.10

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

0.00 0.02 0.04 0.06 0.08 0.10

Co predicted

Co measured

Cu predicted

Cu measured

a.u.

wavelength, nm

a.u.

wavelength, nm

R² = 0.94 ^a LV = 2

Co predicted

Co measured

RMSECV = 0.013/0.004 ^b R² = 0.84/0.98 ^b LV = 2

Cu predicted

Individual calibration series for Co(II) and Cu(II) nitrates

(9)

PRACTICAL APPLICATION

• Calibration sample set for PO

₄^3-

• 9 samples

• 0–0.96 mg/L with 0.12 mg/L step

• Calibration sample set for F

^-

• 11 samples

• 0–0.4 mg/L with 0.04 mg/L step

• Test set: 5 samples from tap, rivers (Neva, Volga, Tatyanka)

and lake Kaban

(10)

PRACTICAL APPLICATION

0.0 0.1 0.2 0.3 0.4

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

RMSECV = 0.031 ^a R² = 0.99 LV = 2

RMSECV = 0.029 ^b R² = 0.96 LV = 2

F- predicted

F- measured

PO43-predicted

PO4

3-measured

a.u.

wavelength (nm) emission of Cu(I) complex (1)

PO43- complex, absorption spectrum

a.u.

wavelength (nm)

emission of Cu(I) complex (2) F- complex,

absorption spectrum

r. Tatyanka r. Volga l. Kaban r. Neva tap water 0.00

0.05 0.10 0.15 0.20 0.25 0.30

samples

concentration of F- , mg/L ^reference

predicted MSE = 0.54%

0.05 0.10 0.15 0.20

0.25 RMSEP = 0.07

R² = 0.65 RMSEP = 0.07

R² = 0.97 MSE = 0.34%

concentration of PO3- 4, mg/L

samples

reference predicted

0.05 0.10 0.15 0.20 0.25 0.30

samples

concentration of F- , mg/L ^reference

predicted MSE = 0.54%

0.05 0.10 0.15 0.20

0.25 RMSEP = 0.07

R² = 0.65 RMSEP = 0.07

R² = 0.97 MSE = 0.34%

concentration of PO3- 4, mg/L

samples

reference predicted

0.0 0.1 0.2 0.3 0.4

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

450 500 550 600 650 700 750 800

0.0 0.2 0.4 0.6 0.8 1.0

RMSECV = 0.031 ^a R² = 0.99 LV = 2

RMSECV = 0.029 ^b R² = 0.96 LV = 2

F- predicted

F- measured

PO43-predicted

PO4

3-measured

a.u.

wavelength (nm) emission of Cu(I) complex (1)

PO43- complex, absorption spectrum

a.u.

wavelength (nm)

emission of Cu(I) complex (2) F- complex,

absorption spectrum

Determination of fluoride and phosphate in surface water

(11)

CONCLUSIONS

• Ir(III) and Cu(I)-based complexes are suitable light sources for OMS

• Ir(III) luminescent complexes have bright controlled emission

• Cu(I) complexes are easier to produce, cheaper, and environmentally friendly

• Using UV flashlight instead of laser diode as excitation source is more convenient

• Developed OMS allows determination of fluoride

and phosphate in surface waters with high accuracy

(12)

MOLECULAR EMITTERS AS A TUNABLE LIGHT SOURCE FOR OPTICAL MULTISENSOR SYSTEMS

A n a s t a s i i a S u r k o v a

, A l e k s a n d r a P a d e r i n a

, A n d r e y L e g i n

, E l e n a G r a c h o v a

, D m i t r y K i r s a n o v

MOLECULAR EMITTERS AS A TUNABLE LIGHT SOURCE FOR OPTICAL

MULTISENSOR SYSTEMS

OPTICAL MULTISENSOR SYSTEM (OMS)

• Multisensor system – an analytical device

• composed of two or more sensors

• optimized for a particular analytical task

• employs chemometrics to maintain accuracy

• Advantages

• inexpensive

• portable

• on-site/on-line implementation

• OMS composed of

• light sources

• photodetectors

• optical fibers

• 3D-printed parts, etc.

Example of OMS

PURPOSE OF THIS STUDY

• To develop OMS prototype based on

molecular emitters as a tunable light source

• To study a real-life applicability of the

developed prototype

MOLECULAR EMITTERS AS A LIGHT SOURCE

• Properties

• laser diode excites the emission of molecular emitters

• Requirements to choose emitters

• absorption spectrum must not overlap with emission spectrum

• excitation radiation must fit into the absorption maximum

• brightness (quantum yield of emission)

• emission wavelength in solid phase

• Advantages

• high versatility

• short analysis time

• adjustment of the emission wavelength for a specific application

EXAMPLES OF MOLECULAR EMITTERS

Ir( III ) compl e xe s Cu( I) com pl exe s

MOLECULAR EMITTERS AS A LIGHT SOURCE

Ir( III ) compl e xe s Cu( I) com pl exe s

Emission spectra of the mixtures

EXPERIMENTAL

(1) (2)

RESULTS FOR MODEL SOLUTIONS

Ir( III )- bas ed OM S Cu( I)- ba se d OM S

Individual calibration series for Co(II) and Cu(II) nitrates

PRACTICAL APPLICATION

• Calibration sample set for PO

• 9 samples

• 0–0.96 mg/L with 0.12 mg/L step

• Calibration sample set for F

• 11 samples

• 0–0.4 mg/L with 0.04 mg/L step

• Test set: 5 samples from tap, rivers (Neva, Volga, Tatyanka)

and lake Kaban

PRACTICAL APPLICATION

Determination of fluoride and phosphate in surface water

CONCLUSIONS

• Ir(III) and Cu(I)-based complexes are suitable light sources for OMS

• Ir(III) luminescent complexes have bright controlled emission

• Cu(I) complexes are easier to produce, cheaper, and environmentally friendly

• Using UV flashlight instead of laser diode as excitation source is more convenient

• Developed OMS allows determination of fluoride

and phosphate in surface waters with high accuracy

ACKNOWLEDGEMENTS

• Saint Petersburg State University

• PostDoc program

• RSF project #19-79-00076

• Samara State Technical University

• CSAC2021 organizers