Effect of Plasmonic Silver Nanoparticles оn the Photovoltaic ... - Core

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ScienceDirect Physics Procedia 73 (2015) 114 – 120

4th h International Confereence Photon nics and Info formation Optics, O PhIO O 2015, 28-330 January 2015 2

Effectt of plasm monic siilver nannoparticlles ɨn th he photovvoltaic p propertie es of Grraetzel so olar cellss D.A. K Kislov * Center of Laser and Informationa al Biophysics,Oreenburg State Uniiversity, Orenburg g, 460018 Russiaa

Absttract It is shown that the addition of silver s nanoparticles in the coonstruction of solar s cells lead ds to a significaant increase in n their o the capacitiv ve and transportt properties Graetzel efficiiency. Apart frrom that found a significant efffect of silver nnanoparticles on solarr cells. ©©2015 Published by Elsevier B.V. B.V. This is an open access article under the CC BY-NC-ND license 20 015The TheAuthors. Authorrs. Published byy Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer--review under rresponsibility of the National Research R Nucleear University MEPhI M (Moscow w Engineering PPhysics Institutte). Peer-review under responsibility of the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute)

Keyw words: surface plaasmons; metal nannoparticles; titaniium dioxide; dye molecules; nanocluster; dye-sensiitized solar cell (D DSSC).

1. In ntroduction Graetzel G electrrochemical ceells or photovoltaic cells baased on titaniium dioxide are a one of thee most modern n and advaanced represenntatives of thee third generattion solar cellss. Through the developmen nt by Michael Graetzel [O'R Regan et al. (1991)] dye sensitized sollar cells maniffested by increeasing attentio on nowadays. This T type solarr battery is larrgely promisin ng, as they arre made of ch heap eco-friend dly materials and do not reequire com mplex equipmeent during prroduction. Ceells have a siimple structurre, good resistance to tem mperature chaanges; effecctively absorbb radiation on different anglles of incidencce, durable an nd easy to operrate. Im mprovement oof the Graetzeel cells characcteristics is coonstantly in work. w One of perspective p m methods to enh hance the performance p iis to use clustters of nanopaarticles with pplasmonic pro operties in thee solar cell deesign [Kislov et al. (201 14), Atwater et al. (2010)]. Metallic M nanopparticles are work w as subwav velength antennnas which usse plasmonic near-field n to in increasing effeective abso orption cross-ssection in dye-sensitised meesoporous sem miconductor (F Fig. 1).

* Corresponding C autthor. Tel.: +7-9055-883-21-22. E-mail E address: [email protected]

1875-3892 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) doi:10.1016/j.phpro.2015.09.130

D.A. Kislov / Physics Procedia 73 (2015) 114 – 120

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2. Experimental E l 2.1. Fabrication of dye-sensitizzed solar cell Used U glass witth a conductivve coating (Sn nO2:In; Rƶ=500 Ohm). TiO2 paste depositted on the glasss, film thickn ness is equ ual to 30-40 μ μm. For fabriccation pastes we used TiO 2 nanopowderr (particle size of 25 nm) aand were mix xed in acettic acid with addition of Triton-X100 T (n nonionic surfa factant). For effective e dispeerse we used the ultrasonicc bath (ultrrasonic treatm ment time ~ 300-40 min) [Kisslov, Ponomarrenko (2014)]].

Fig. 1. Basic idea ddemonstration. Dyye molecules in th he Graetzel cell, trapped in a regio on of locally enha anced near-field oof metal nanopartticles free charge carrierrs. generate more fr

After A depositiion of the paaste samples were dried inn air at room m temperaturee. It is necesssary to reducce the mecchanical stresses in TiO2 fiilm. After dry ying the sampples were placced in a muffl fle furnace andd annealed fo or 145 min nutes at a speccial temperatuure regime (Fig g. 2). As a ressult, the titaniu um dioxide naanoparticles arre sintered between them mselves and thhe glass conduuctive surfacee, forming a seemiconductor nanoporous layer.

Fig. 2. Annealing temperature regime r of glass with w TiO2 paste

Fig. 3. The anthocyanin n absorption spect ctrum in ethanol

Further F nanopporous-TiO2 electrode e staiined anthocyaanin solution in ethanol (Fig. ( 3). Staiining time was w 30 min nutes. Dye moolecules are deposited d on th he nanoparticcles surface, forming fo strong g chemical boonds. As a ressult of the film color chaanged from white w to purple. Nanoporous-T N TiO2 electrodee was connectted to the couunter electrod de through a dielectric d spaccer (thickness ~100 ȝm)). Previously carbon catalyyst deposited on o the counterr electrode. The space betw ween the electtrodes is filled d with

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D.A. Kislov / Physics Procedia 73 (2015) 114 – 120

electtrolyte. The ellectrolyte connsists of a solu ution of iodinee I2 (0,05 M) and potassium m iodide KI (00.5 M) in ethy ylene glycol. In the elecctrolyte formed redox ion paairs 3I- and I33-. 2.2. Synthesis of ssilver nanoparrticles with a plasmon p resonnance In ou ur work we investigate i thhe effect of metal nanopartiicles with a plasmon rresonance on n the mechanissms of electtrochemical pphotovoltaic cells based on nanostructureed titanium diioxide. To perrform the tasks we have syn nthesized silveer nanoparticlles by vich et al. (19551)]. citrate meethod [Turkev The figure fi 4 shows absorption spectrum prepared hydrosol. Using atomiic force microoscopy and ph hoton on spectrosco opy we havee investigated d the correlatio average sizes s of silver nanoparticless. The average size is approx ximately 35-45 5 nm. Four types Graetzel solar ceells samples with c s of nanoparticcles were prep pared. various concentrations The sam mple, what did d not contain nanoparticless was standard sample. The remaining 3 samples conttained c various concentrations of nanosilverr. Fig.4 4. Absorption speectrum of silver nanoparticles hydrrosol prepared byy citrate reduction. (Plasmon ressonance at Ȝmax = 421 nm)

2.3. Measurementts Figure F 5 show ws experimenntal setup forr the measureement curreent-voltage chharacteristics and a maximum m power of sam amples at different cconcentrations of silver nanoparrticles. Meaasurements weere carried outt at constant illlumination. Figure F 6 depiccts the experiment for a ty ypical photoellectric transsient measureement system [Li et al. (20 012)]. The tran ansient measurements aree based on a large l bias illumination geneerated h a power witthe diode to produce p the ph hotocurrent ddensity with (JSC) and the phootovoltage (V VOC) under sh hortcircuit annd the open n-circuit condditions, respectively. To probe p the tran ansient decaays, a pulsedd YAG laserr is employeed to perturb rb the phottostationary sstate for whicch the transieent profiles, either Fig.5 5. Experiment to measure photocuurrent and photov voltage ǻJSCC(t) or ǻVOC(t)). LED L gives biaas light continnuously. Experiment was conducted on n the observaation of the ccell response to an addiitional single llaser pulse at different bias light intensityy. To ensure that t the small--amplitude per erturbation critterion of th he system is ffulfilled, the intensity i of th he probe is addjusted to be less than 5% %-10% of the bbias intensity y. The resulting photocurrrent and phottovoltage transient are recorrded on an oscilloscope.

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D.A. Kislov / Physics Procedia 73 (2015) 114 – 120

3. Results R and d discussion 3.1. ɋurrent-volttage curves. Efficiency. Ef

Fig. 6. Experiment too measure photocuurrent and photov voltage decays wi with the continuou us bias light and a single laserr pulse.

The figgure 7 show ws the current-volltage curves and power curvves of the sam mples. It can be sseen that the silver nanoparticlles in saample design alloow generate more photocurren ent. Moreeover, photo currrent rises up,, with increasing of concenttration nanosilver in the cell. The annalysis showss, that plasmonic maximum nanoparticlles concentrattion in the solarr cell, inccreases efficiency more than 2 times h the in compaarison with standard saample (see tab ble 1).

Fig. F 7. The currennt-voltage characcteristic (a) and po ower curves (b) oof cells with addittion of different concentrations c off silver nanoparticcles

CAg, mg/l

Table 1. Th he filling factor annd the efficiency of the samples Fiill Factor (FF)

Efficciency, %

0

0,44696

0,,0082

26,85

0,46598

0,000943

40,28

0,41984

0,001142

53,7

0,47399

0,001734

3.2. Photoelectricc transients off photocurrent and photovooltage decays To T investigatee the capacitivve and transpo ort properties of the photov voltaic cell sam mples, was coonducted a serries of exp periments on thhe observationn of the cell reesponse to an additional sin ngle laser pulse at different light intensity y bias.

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Fig. F 8. Typical phhotoelectric transiients of (a) photoccurrent decays annd (b) photovoltag ge decays represe enting the kineticc processes electro on transport annd charge recombbination of a DSSC under short-cirrcuit and open-cirrcuit conditions, respectively r (CAgg=53,7 mg/l).

Measurements M were carriedd out in two cells modes:: short-circuitt mode ( 'J SCC (t) ) and op en circuit mo ode ( 'VOC e approximateed by exponen ntial functions: O (t) ).The obttained curves (fig. 8) can be 'J SCC (t)

§ t · 'J ˜ exp p¨ ¸ , © WC ¹

'VOC (t)

§ t · 'V ˜ exp e ¨ ¸ , © WR ¹

(1)

wherre, 'V and 'J - the ampliitude of the op pen-circuit vooltage and short circuit curreent from a sinngle laser pulse, W C - colllection time ccoefficient, W R - the time co oefficient for ccharge recomb bination. The T figure 9 shhows short-cirrcuit photocurrrent density aand open-circu uit photovoltaage from a sinngle laser pulse as a funcction of bias inntensity at diffferent concenttrations of silvver nanoparticcles.

Fig. 9. 9 Short-circuit phhotocurrent densiity (a) and open-ccircuit photovoltaage (b) from a sin ngle laser pulse ass a function of biaas intensity at diffferent co oncentrations of ssilver nanoparticlles

The T amplitude of short circuuit current an nd open circuiit voltage in the t samples with w the highesst concentratiion of silveer nanoparticlees more than in i 2 times high her than in thee standard sam mple. Moreover M figuure 10 shows changes of th he time charaacteristics. Th he addition off silver nanopparticles leadss to a significant processes acceleratioon.

D.A. Kislov / Physics Procedia 73 (2015) 114 – 120

Fig. 10. Plots of eleectron collection time

WC

(a) and electron lifetimee

WR

(b) as a func ction of bias intennsity.

3.3. Chemical cap apacitance Using U this daata was calcuulated the electrochemical capacity of the samples and the diffuusion coefficient of pho otoelectrons innjected into thhe titanium dio oxide film. Eleectrochemicall capacity is proportional p too the density of o trap states (DOS) at the VOC levell under the bias irradiationn. Specifically y, C is measu ured with the probe perturrbation und der bias irradiaation to reflectt the DOS at that t Fermi levvel giving the VOC. By B definition, the capacitannce is given by y: 'Q (2) C . 'VOC Wh here the charge density ǻQ due to the prrobe light irraadiation is obttained through h time integraation of the current tran nsient determinned under thee short-circuit condition; thee potential diffference ǻV due d to the probbe irradiation is the timee-zero amplituude determineed under the open-circuit o coondition. For this t it is necesssary to calcullate the total charge c passsing through tthe working ellectrode (3) (3) 'Q ³ 'J SC (t') dtt' t

In I the sampless with the highhest concentraation of silverr nanoparticless charge densiity increased m more than 2.7 7 times (fig g. 11a). Figuree 11b shows thhe curves of the t electrocheemical capacittance change. It is seen, thaat by increasing the biass light intensity the capacitty of cells inccreases. The ppresence in th he structure off the cells of silver nanopaarticles sign nificantly incrreases the capaacity (for sam mple with CAg= =53,7 mg/l 1.3 3 times compaared to the stanndard sample)).

t working electtrode (a) and elecctrochemical capa acity (b) of the sam amples with and without w Fig. 11. Changing the charge density passing through the nanopparticles.

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3.4. Diffusion ccoefficient of the t photoelecttrons In n addition, uusing the exxperimental data was calcu ulated diffusioon coefficientt of photoelecttrons: L2 (4) , D 2.777 ˜W C wherre L - the thhickness of the t layer TiO O2. In our expeeriment, the tthickness of the t layer TiO O2 was 40 ȝm. Figure F 12 shoows the calcculated curvees of the diffu usion coefficiient changes. The graphs show that with h increasing bias light inntensity the diffusion coeffficient increaases, which means m the accelerated flow w of the chargge transfer proocess. Furtherrmore, the addiition of sillver nanopaarticles in the cell conssiderably incrreases the difffusion coeffiicient and hencce in the presence of pllasmonic nan noparticles charrge transfer processes occuur more quick kly. Since the sample witth the highhest concentrration of nano oparticles the average diffuusion coefficieent is 1.22 timees larger than the average diffusion coefficient in the standard s sampple.

Fig. 12. Chang ging the diffusion coefficient of eleectrons in the sam mples with and witthout nanoparticlees.

4. Conclusions Thus, T it is show wn that the adddition of silv ver nanoparticcles in the con nstruction of solar cells leaads to a signifficant increease in their eefficiency. Appart from that found a signnificant effect of silver nano oparticles on the capacitivee and transsport propertiees Graetzel soolar cells.

Ack knowledgemen nts This T work wass supported byy the Russian Foundation foor Basic Reseaarch (project no. n 15-08-041132 a) and Co ouncil President of the R Russian Federration on gran nts for state ssupport of you ung Russian scientists (graant of Presideent of Russsian Federatioon, project no. ɋɉ-1340.201 15.1).

Refeerences Atwaater, H.A., Polmann, A., 2010. Plasm monics for improved photovoltaicc devices, Nature 9, 205-213. Kislo ov, D.A., Ponomaarenko, D.V., 2014. Effect of silver nanoparticles onn the basic param meters of photovoltaic dye-sensitizzed solar cell, Absstracts of the All-Russiaa Conference "Unniversity complex x as a regional cennter for education n, science and cullture ", OSU, Oreenburg, 1377-138 83. Kislo ov, D.A., Isupov, A.Yu., 2014. Dyee-sensitized solarr cell containing pplasmonic silver nanoparticles, n Ru ussian-Japanese C Conference «Chem mical Physics of Moleccules and Polyfunnctional Materials»: Proceedings. OSU, Orenburg, Russia, 10-12. Li, L..L., Chang, Y.C., Wu, H.P., Diau, E.W.G, 2012. Ch haracterisation off electron transpo ort and charge rec combination usingg temporally reso olved ws in Physical Ch hemistry 31, 420--467. and frequency-doomain techniquess for dye-sensitiseed solar cells, Intternational Review O'Reg gan, B., Gratzel, M M., 1991. A low--cost, high-efficieency solar cell baased on dye-sensittized colloidal TiO2 films, Naturee 353, 737–740 Turkeevich, J., Stevenson, P.C., Hillier, J., 1951. A study y of the nucleationn and growth pro ocesses in the synthesis of colloidaal gold, Discuss. Faraday Soc. 11,, 55-75.