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CONTACT PERSON REFERENCES
Liquid-Phase Exfoliated GeSe Nanoflakes For Photoelectrochemical-Type Photodetectors
Gabriele Bianca, 1,2 Marilena Isabella Zappia,3,4 Sebastiano Bellani,1,3 Michele Serri,1 Leyla Najafi,1,3 Beatriz Martín-García,1 Reinier Oropesa-Nuñez, 3 Tomáš Hartman, 5 David Sedmidubský,5 Vittorio Pellegrini,1,3ZdeněkSofer,5 Gennaro Chiarello4 and Francesco Bonaccorso 1,3
1 Graphene Labs, Istituto Italiano di Tecnologia, via Morego 30, Genova, Italy, 2 Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, viaDodecaneso 31, Genova, Italy , 3 BeDimensional Spa., via Lungotorrente Secca 3d, Genova, Italy, 4 Department of Physics, University of Calabria, Via P. Bucci cubo
31/C, Rende (CS), Italy, 5 Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, Prague 6, Czech Republic
WORKSTATION
Gabriele Bianca
PhD student IIT –Graphene Labs, Genoa (Italy)
Conclusion
GeSe-based Electrode Fabrication and Experimental Setup
Airbrush
GeSe nanoflakes
Graphite paper
Hot plate
- Industrially compatible- Scalable- Flexible electrodes
WorkingElectrode
ReferenceElectrode
CounterElectrode
V
A
SPRAY-COATINGDEPOSITION
PEC-WORKSTATION
Liquid Phase Exfoliation Process2
GeSe nanoflakesDispersion Sonication Purification
ω
1stste
p
GeSe bulk
3rd step2nd step
Advantages:• Scalable production of GeSe nanoflakes-based
inks• High-processability through printing techniques
Equipment: • Sonic bath• Centrifuge
Solvent: • 2-propanol (IPA)
The obtained performances are superior to those of several self‐powered and low‐voltage solution‐processed photodetectors, approaching theones of self‐powered commercial UV–Vis photodetectors. Our results open the way towards the use of 2D GeSe in novel PEC systems.
0.5 M H2SO4
1. M.I. Zappia, G. Bianca et al. Adv. Funct. Mater. 2020, 19095722. F. Bonaccorso et al., Adv. Mater., 2016, 28, 6136
Layered monochalcogenides have been predicted as efficient materials for photoelectrochemical (PEC) applications.1 In this work, single-/few-/multi-layer flakes of germanium selenide (GeSe) have been produced by liquid-phase exfoliation of GeSe crystals to develop water splittingsystem and self-powered PEC-type photodetectors. The devices show responsivities up to 0.32 AW-1 at -0.5 Vvs. RHE under 455 nm excitationwavelength in acidic electrolyte (0.5 M H2SO4), in which they also stably operate.
Introduction
Morphological Characterization
0 40 80 120 1600
10
20
Co
un
ts (
%)
Lateral size (nm)
36 nm
0 5 10 15 200
10
20
Counts
(%
)
Thickness (nm)
2.9 nm
100 150 200 250
A2gIn
ten
sity (
a. u
.)
Raman shift (cm-1)
Bulk
Nanoflakes
A1g
B13g
20 40 60 80
Nanoflakes
511
311
400
111
Inte
nsity (
a. u
.)
2q (°)
201
Bulk
Responsiv
ity
(A W
-1)
Photoelectrochemical Characterization of GeSe PEC-type Photodetectors
-0.4 -0.2 0.0 0.2-80
-60
-40
-20
0
455 nm
505 nm
625 nm
100 150 200 250 300 350 400
A1g
GeSe nanoflakes
Fresh GeSe photoelectrodes
Tested GeSe photoelectrodes
B13g A2
g Si
(substrate)
-0.4 0.0 0.4 0.8 1.2 1.6
10-3
10-2
10-1
100
95.5 mA W-1
455 nm
505 nm
625 nm
316.6 mA W-1
-0.4 0.0 0.4 0.8 1.2 1.6
455 nm
505 nm
625 nm
248.3 mA W-1234.5 mA W-1
-0.4 0.0 0.4 0.8 1.2 1.6
301.7 mA W-1
455 nm
505 nm
625 nm
94.9 mA W-1
dark current density:
>50 mA cm-2
Potential (V vs. RHE)
0.5 M H2SO4 1M KCl 1M KOH
No chemical degradation
Curr
ent
density
(mA
cm
-2)
Potential (V vs. RHE)
Layered GeSe
Top-view Side-viewDepending on pH and thickness,GeSe nanoflakes can act asphotocatalysts for hydrogenand oxygen evolution reaction(HER and OER).
25 µm 25 µm 25 µm1 2 3 4 5 6 7
-6
-4
-2
0
-6
-4
-2
00 2 4 6 8 10 12 14
H+/H2
O2/OH-
Ener
gy (
eV)
Number of layers (-)
pH (-)
Raman shift (cm-1)
Inte
nsity
(a.u
.)