HAL Id: hal-01326324
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01326324
Submitted on 7 Jun 2016
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Synthesis of Ni-poor NiO nanoparticles for DSSC-p
applications
Baptiste Polteau, Franck Tessier, François Cheviré, Laurent Cario, Stéphane
Jobic, Fabrice Odobel
To cite this version:
Baptiste Polteau, Franck Tessier, François Cheviré, Laurent Cario, Stéphane Jobic, et al.. Synthesis
of Ni-poor NiO nanoparticles for DSSC-p applications. E-MRS 2015 Spring meeting, May 2015, Lille,
France. �hal-01326324�
Synthesis•of•Ni-poor•NiO•nanoparticles•
for•DSSC-p•applications•
Baptiste••Polteau•
a
,•Franck••Tessier•
a
,•François••Cheviré•
a
••
Laurent••Cario•
b
,•Stéphane••Jobic•
b
,•Fabrice•Odobel•
c
••
a
•Institut•des•Sciences•Chimiques•de•Rennes,•Université•de•Rennes•1,•France•
b
•Institut•des•Matériaux•Jean•Rouxel,•Université•de•Nantes,•France•
c
•CEISAM,•Université•de•Nantes,•France•
Nickel•precursor•synthesis•&•characterizations•
Thermal••decomposition•under•air•atmosphere•
Thermal••decomposition•under••
ammonia•atmosphere•
Conclusion•
References•
p-DSSC•performances•
O
ver• the• last• decade,• p-type• semiconductors• (SC)• have• known• a• renewed• interest.• Indeed• these• materials• may• have• potential•
applications•for•light-emitting•diodes,•transistors,•solar•cells,•etc.•Since•the•achievement•of•the•first•Dye Sensitized Solar•Cells•(DSSC)•
by•Grätzel•
[1]
•in•1991•a•new•generation•of•solar•cells•has•been•developed•
[2]
•where•the•n-type•SC•is•replaced•by•a•p-type•one.•This•leads•
to• the• photo-injection• of• holes• instead• of• electrons• in• the• circuit.• To• date• nickel• oxide• (NiO)• is• the• reference• p-type• semiconductor.•
However• yields• are• still• far• from• those• of• n-DSSC• and• many• studies• aim• to• replace• NiO• by• other• systems• such• as• CuAlO
2
,• CuGaO
2
,•
CuCrO
2
• or• NiCo
2
O
4
• nanoparticles.• Following• our• recent• synthesis• of• N• doped• ZnO• with• stabilization• of• p-type• charge• carriers•
[3]
,• we•
focus• now• on• the• preparation• of• N• doped• NiO• nanoparticles• to• improve• the• p-type• conductivity• of• NiO.• We• study• here• the• chemical•
reactivity•of•a•nickel•oxyhydroxide•precursor•under•air•and•ammonia•that•conducts•to•nanostructured Ni-poor•NiO
•[4]
.•
!
Synthesis•of•an•original•nickel•precursor•with•very•small•particle•sizes•and•high•specific•surface•area.•The•determination•of•
the•Ni
2+/Ni
3+•ratio•is•leading•to•the•exact•formulation•Ni
3
O
2(OH)
4•!
Decomposition•of•Ni
3O
2(OH)
4•under•air•at•temperature•lower•than•500°C•forms•strong•non-stoichiometric•NiO•nanoparticles•
with•high•nickel•vacancy•concentration•
!
Stabilization of nitrogen doped NiO by decomposition of Ni
3O
2(OH)
4•under•ammonia•atmosphere•at•250°C•
!
Characterization of Ni-poor NiO and NiO:N nanoparticles in p-DSSC in progress
•[1]•B.•O'Regan,•M.•Grätzel,•Nature•353,•737-740•(1991).• • [2]•F.•Odobel,•L.•Le•Pleux,•Y.•Pellegrin,•E.•Blart,•Acc.•Chem.•Res.,•43,•1063•1071,•(2010).• • [3]•B.•Chavillon,•L.•Cario,•A.•Renaud,•F.•Tessier,•F.•Cheviré,•M.•Boujtita,•Y.•Pellegrin,• E.•Blart,•A.•Smeigh,•L.•Hammarström,•F.•Odobel,•S.•Jobic,•J.•Am.•Chem.•Soc.•134,•464-470• (2012).• •
[4]B.•Polteau,•F.•Tessier,•F.•Cheviré,•L.Cario,•S.•Jobic,•F.•Odobel (2015)•to•be published.•
•Specifications•for•SC-p•:•
•
-
Nanoparticles•(high•
specific•surface•area)•
-
High•mobility•of•charge•
carriers•(holes)•
-
Low•energy•valence•band•
•
Conversion•efficiency•:••
Energy•difference•between•VB•
(SC-p)•and•redox•potentiel•
(mediator)••V
oc•
•
Problematics•:••
Quest•of•new•materials•
Photo-injection•of•holes•from•the•excited•dye•to•the•
valence•band•of•the•p-type•semi-conductor••
NiSO4, 6H2O NaClO + NaOH Precipitation•route• Black•color• Nickel•oxyhydroxide•(XRD)• Agglomerated•nanoparticles• •2-3nm•(TEM)• Specific•surface•area• •230•m²/g•(BET)•Oxyhydroxide•NiO
x(OH)
y••formulation•?
•
0 0 50 - 0 5 10 0 50 15 200 250 -°C) 0 100 200 300 400 500 0 50 100 150 200 250 300 1 /• (m o l. Oe. e m u -1) Temperature (°C) 1/C 0 2 4 6 8 10 0 50 100 150 200 250 300 Mom en t/g (em u.g-1 ) Temperature (°C) 63% 37% Ni2+: 853.79 eV Ni3+: 855.37 eV Ni0: 852.6 eV Ni2+: 854.6 eV Ni3+: 856.1 eV XPS•Ni(2p)•: - Ni 3+ 2p 3/2 binding• energy
(855.8•eV)• with surface• area•63•% - Ni 2+ 2p 3/2 binding• energy
(854.3• eV)• with surface• area•37• % ! Ni 2+ /Ni 3+• ratio•••½ Magnetism : - Curie•Constant•=•0.63•SI• units - • eff =••(8 ! C)•=•2.24• • B • eff (Ni 2+ )•=•3.2 • B • eff ( Ni 3+ )• =• 1.7 • B " Ni 2+ /Ni 3+• ratio• • ½ with
NiOOH
1.33•=•Ni
3O
2(OH)
4•=
•Ni
2+1Ni
3+2O
2(OH)
4•65 75 85 95 105 0E+00 5E-07 1E-06 2E-06 0 100 200 300 400 500 600 700 800 W e ig h t (%) Inten si ty ( a. u) Temperature (°C) H2O TGA O2 O2-ou NH2 -CO2 -2 -1 0 1 2 70 80 90 100 0 100 200 300 400 500 600 700 800 T em pe ratu re Di fferenc e (° C ) W e ig h t ( %) Temperature (°C) 2 1 3 Exo •TGA/TDA/Mass•spectroscopy•:• • 1-•Tamb-110°C•••Surface•dehydration•(desorption• of•H2O•molecules)• • 2-•110-200°C•••Elimination•of••OH-••groups••in•• water••form•without•oxygen•loss••-•Formation•of•• Ni-poor•NiO• • 3-•200-500°C•••Elimination•of•O2•groups•excess••-• Transformation•of•Ni-poor•NiO•into•stoichiometric• NiO• (111) (220) (3 11 ) (22 2 ) (200) Tamb 700°C 2•Theta (°)• Intensity (a.• u .)
!
In•situ•XRD•patterns••:• • - Cubic•NiO•structure•(NaCl•type)•formation• at•150•–•200°C• • - Higher•crystallinity•with•temperature• T°C Tamb Time 2 hours 10°C/min Nickel•oxyhydroxide•precursor• Muffle•Furnace• Thermal••decomposition•• 250°C•!•T•!•800°C• Specific•surface•area,•TEM,•crystallite•sizes,• density•and•oxygen•analyses• Characterizations•Experimental•procedure•
-0,1 0,1 0,3 0,5 3,5 4,5 5,5 6,5 200 300 400 500 600 700 800 x i n N i1-x O De n si té Temperature (°C) NiOStoechio 19 24 29 34 200 300 400 500 600 700 800 % w t O 0 100 200 300 200 300 400 500 600 700 800 NiOStoechio S p e ci fi c su rfa ce a re a ( m²/ g ) 0 50 100 200 300 400 500 600 700 800 C ry sta ll it e s iz e s (n m) 200 300 400 500 600 700 800 C o lo rEvidence•of•Ni-poor NiO nanoparticles
!
Physicochemical•characterizations••:• • - Black•NiO•nanoparticles•at•temperatures•••500°C•and•green• stoichiometric•NiO•at•high•temperatures• • - Very•small•crystallite•and•particle•(TEM)•sizes•for•low• temperature•decomposition• • - High•specific•surface•area• •200•m².g-1••at•250•and•300°C•in• agreement•with•particle/crystallite•sizes• • - Strong•oxygen•excess•in•NiO•nanoparticles• !•NiO1+x•or•Ni1-xO•formulation•?•• - Low•NiO•densities•at•low•temperature•!•high•Ni•non-stoichiometry• Nickel precursor 350°C Ni3N phase 2•Theta (°)• Intensity (a.• u .) XRD•patterns•:• - Cubic•NiO•structure•(NaCl•type)•at••••• T•••250•°C• • - No•influence•of•temperature on•NiO stucture•crystallinity• • - Hexagonal•Ni3N•structure•formation• at••T• •300•°C• XPS•N(1s):• - Absence•of••N•1s•signal•in•NiO•at• T•=•250°C•under•air• • - N•1s•peak•at•398.2•eV•in•NiO•at• T•=•250°C•under•ammonia•• •••••• •N3-•insertion• • •