Università degli Studi di Ferrara Solid State Dye Solar Cells: Development of Photoanode Architecture for Conversion Efficiency Improvement Internal supervisor: Vincenzo Guidi External supervisor: Giampiero Ruani Tanja Ivanovska 1 st Year PhD Talk 6.11.013, Ferrara
glass FTO electrolyte dye Pt Vac. ev -4 V -5 V -6 V TiO Dye E(I - /I 3- ) Pt S + hν S * S * S + + e S + + e S I 3 + e 3I m-tio FTO glass c-tio -7 V O'Regan and Gratzel, Nature 353, 737 (1991) Low cost materials abundant low purification Low energy-consumption manufacturing process highest temperature 450 C Electron transport, light absorption and hole transport are each handled by different materials in the cell
Historic evolution of the Dye Sensitized Solar Cell Technology Snaith, J. Phys. Chem. Lett. 4, 363 (013) Limiting the electron-hole recombination - improve the photogenerated electron mean free path - improve the charge separation and reduce the charge recombination dynamics
Absorption (a.u.) Grain size (cm) Intensity (a.u.) Introduction of TiO colloidal solution 10 Surface treatment of photoanode 9 8 1300 100 1100 1000 900 800 700 600 500 400 300 Alternative method to TiCl 4 post-treatment 7 6 00 100 0-100 00 400 600 800 Raman shift, (cm -1 ) 5 Colloidal solution of 5 nm TiO nanoparticles Drop casted on to TiO photoanode surface Sintered at 150, 350 and 450 C for 0min SEM imaging of TiO photoanode surface 4 3 100 00 300 400 500 Annealing temperature ( C ) Micro-Raman size crystalline investigation 0,5 0,0 no post treatment @150 C @350 C @450 C 0,15 0,10 0,05 0,00 350 400 450 500 550 600 650 700 750 800 (nm) without with colloidal treatment UV-Vis Absorption measurements
Cell efficiency (%) 3,6 Cell Thickness (µm) J SC (ma/cm ) V OC (V) FF (%) η (%) Plain P5 14,5-7,45 0,66 6,99 3,10 150 14,4-7,36 0,69 60,1 3,06 350 14,0-7,6 0,68 58,01 3,01 450 14,0-8,3 0,69 60,9 3,46 3,3 3,0,7 IPCE=LHE x φ inj x φ coll Open Circuit Voltage Decay Technique (OCVD) 0 50 100 150 00 50 300 350 400 450 500 Annealing temperature C) large perturbation of the Fermi level a trapping/detrapping model different possibilities for interfacial charge transfer Bisquert et al., JACS 16, 13550 (004) n k b e T dv dt oc 1
10 c) Without TiO colloidal treatment With TiO colloidal treatment Changing electrolyte n (s) 1 0,1 b) a) 0,01 0,0 0,1 0, 0,3 0,4 0,5 0,6 0,7 0,8 V OC (V) Introducing compact layer
Incorporating SWCNT in the of TiO mesoporous matrix x = 0.15 x = 0.07 x = 0.3 x = 0.8 x = 0.04 x = 0 Pros: Sufficient distribution in the mesoporous film Conductivity increase of several orders of magnitude Cons: Coverage of the nanotube wall Recombination centers glass FTO Pt electrolyte dye SWCNT m-tio FTO glass c-tio TiO colloidal treatment effect
J (ma/cm ) Cell efficiency (%) Solid State DSSC using Spiro-MeOtad as a HCM Ag Spiro-MeOtad dye m-tio FTO c-tio glass Cells employing SWCNTs in the photoanode 0,0 0,6 0,60-0,5-1,0-1,5 0,58 0,56 0,54 0,5 0,50 -,0 -,5 TiO TiO +0,04% CNT TiO +0,07% CNT 0,48 0,46 0,44 TiO +0,15% CNT -3,0 0,0 0,1 0, 0,3 0,4 0,5 0,6 U (V) 0,4 0,40 0,00 0,05 0,10 0,15 SWCNT loading (wt%)
Cell efficiency (%) J (ma/cm ) Colloidal TiO post treatment 0 Cells employing SWCNTs + TiO surface colloidal treatment in the photoanode -1-0,8-3 0,7 Without TiO colloidal treatment With TiO colloidal treatment -4 0,0 0,1 0, 0,3 0,4 0,5 0,6 0,7 0,8 U (V) 0,6 0,5 0,4 Cell d (µm) Isc (ma/cm ) Voc (V) FF (%) n (%) 0,3 TiO 1,1-3,09 0,71 37,88 0,83 TiO +colloidal 1,0-3,5 0,70 46,50 1,15 0, 0,00 0,05 0,10 0,15 SWCNT loading (wt%) Observed shift in cell efficiency relative to the SWCNT loading in the photoanode
Abs (a.u.) Intensity (a.u.) Perovskite Solar Cells CH 3 NH +HI CH 3 NH 3 I+PbCl CH 3 NH 3 PbI 3-X Cl X Perovskite synthesis very sensitive to laboratory conditions Investigation of the spectroscopic properties of CH 3 NH 3 I color Absorption of CH 3 NH 3 I 3-x Cl x on glass substrate 1,8 1,6 1,4 1, 1,0 white yellow brown 1000 800 600 400 (110) (0) (310) PbI (0) (11) PbI (31) (4) (314) (11) PbI brown yellow 0,8 00 0,6 300 400 500 600 700 800 900 (nm) Direct band gap Eg 1,55eV 0,5 1,0 1,5,0,5 3,0 3,5 4,0 ) -1 إ) q Identification of perovskite crystals by XDR
J (ma/cm) Completely solution processable cell Difference in photocurrent with perovskite purity 0-5 -10 However there is an inevitable degradation in air -15 0,0 0,1 0, 0,3 0,4 0,5 0,6 0,7 0,8 U (V) white yellow High J SC =1-15mA/cm, matching the J SC of cells with record efficiencies Michael M. Lee et al., Science 338, 643 (01) J.M. Ball et al., Energy and Environmental Science 6, 1739 (013)
J (ma/cm ) J (ma/cm ) Introducing Graphene in to the electrode architecture Incorporating graphene in to the photoanode Incorporating graphene in to the counterelectrode FTO substrate graphene Graphene photoanode with a compact layer Graphene counterelectrode, without compact layer 5 4 3 1 measured after 1 day 1 0-1 0-1 - -3-4 -5-6 -7-8 -0,1 0,0 0,1 0, 0,3 0,4 0,5 0,6 0,7 0,8 0,9 U (V) - -3-4 -5 measured after 5 days measured after 5 days (dark curve) -6-0,1 0,0 0,1 0, 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 U (V)
Acknowledgements -CNR Bologna Chiara Dionigi DIMO Group Vinca Institute, Belgrade Zoran V. Saponjic Marija Radoicic IMM-CNR Bologna Vittorio Morandi Luca Ortolani Franco Corticelli Fabiola Liscio ICTP-TRIL Programme CNR-EFOR Project (Energie da Fonti Rinnovabili) Thank You for the Attention