Ce projet de recherche est soutenue par le Conseil australien de la recherche par l&#39;octroi de liaison avec CSG Solar Pty Ltd Rao Jing reconnaît son Université de NSW vice-chancelier de bourses postdoctorales. Images MEB ont été prises par Jongsung parc en utilisant le matériel fourni par l&#39;Unité de microscopie électronique de l&#39;Université de NSW.

1. Fabrication de cellules solaires en silicium polycristallin (Animation 3) <ol><li> De dépôt de film de silicium <ol class="lalpha"><li> Préparer l&#39;outil d&#39;évaporation par faisceau d&#39;électrons par l&#39;étuvage à ~ 100 ° C pendant la nuit pour atteindre la pression de base de &lt;3E-8 Torr. Pré-régler le chauffe-échantillon à la température 150 ° C ° en mode veille. </li><li> Utilisation d&#39;un substrat fait de 5x5 cm 2 (10 x 10 cm ou 2) de substrat de verre de borosilicate (Schott Borofloat33), 1,1 ou 3,3 mm d&#39;épaisseur, revêtues avec ~ 80 nm de nitrure de silicium (préparée par PECVD à partir de N 2 et SiH 4 mélange). </li><li> Sonnez de la surface du substrat avec de l&#39;azote sec pour enlever la poussière et le placer dans un porte-échantillon. Purger le sas de chargement, de charger l&#39;échantillon, pomper le sas à la pression &lt;Torr 1E5, et transférer l&#39;échantillon à la chambre principale. Démarrer le chauffe à la consigne de 250 ° C. Pompe pour environ 20 min lorsque la pression atteint 8E-8 Torr ou inférieure. </li><li> Vérifiez que le dopantvolets de source de silicium de source et de l&#39;sont fermés. Préréglées températures de source de dopant à des températures de secours, à savoir la température de la source de phosphore à 700 ° C et la température de source de bore à 1250 ° C. Début e-gun et faire fondre le silicium dans un creuset en augmentant lentement le courant e-gun. </li><li> Quand le courant requis est atteint (à partir de l&#39;étalonnage précédent: ce courant peut varier en fonction de l&#39;e-gun et les conditions de source Si) s&#39;évapore des couches de silicium dopées avec les concentrations requises de P et B: 35 émetteurs nm à 1E20 cm -3 de P ; 2 ~ 3 um absorbeur à 5E15 cm -3 de B; 100 nm champ de surface arrière (FBS) à 4E19 cm -3 de B. Les concentrations de dopant exactes sont réalisés en faisant correspondre des vitesses de dépôt de Si certaines, telle que mesurée par cristal de quartz Moniteur (QCM), avec certaines températures de source de dopant, en utilisant les relations établies à partir d&#39;étalonnage SIMS. </li><li> Après évaporation se fait passer le radiateur, refroidir l&#39;échantillon pour ~ 10 min. TransFer l&#39;échantillon à la charge de blocage, fermer la porte-vanne, évacuer l&#39;sas de chargement et de déchargement de l&#39;échantillon avec le film de silicium. </li></ol></li><li> Silicon cristallisation Si l&#39;échantillon est 10x10 cm 2, il peut être coupé en quatre 5x5 cm 2 morceaux de la taille des cellules avant la cristallisation. Placer un film de silicium déposé sur le verre (film de Si jusqu&#39;à) sur un support en nitrure de silicium rendue rugueuse et revêtue de verre Schott Robax (pour éviter le collage). Chargement dans un four préchauffé à purgé à l&#39;azote 200-300 ° C. Montée en puissance de la température jusqu&#39;à 600 ° C à 3 ~ 5 ° C / min et recuit pendant 30 h. Tour de l&#39;appareil de chauffage du four et laissez refroidir le four naturellement à ~ 200 ° C (2 ~ 3 heures) avant le déchargement de l&#39;échantillon. L&#39;échantillon peut avoir une forme concave en raison du rétrécissement de silicium lors de la cristallisation. Il va aplatir au cours du traitement thermique suivant rapide. </li><li> Activation du dopant et le défaut de recuit (RTA) Placer l&#39;échantillon avec le film cristallisé sur un support en graphite pyrolytique et load à un processeur thermique rapide purgé avec de l&#39;argon. Rampe de la température jusqu&#39;à 600 ° C à 1 ° C / s, puis jusqu&#39;à 1000 ° C à 20 ° C / s, maintenir pendant 1 min, puis refroidir naturellement à ~ 100 ° C et le déchargement. </li><li> Élimination d&#39;oxyde de surface Immédiatement avant l&#39;hydrogénation de l&#39;oxyde de surface formée sur le film de silicium lors de la cristallisation et RTA doit être retiré pour que la surface de silicium à nu du film est exposé à un atome d&#39;hydrogène. Plongez l&#39;échantillon recuit en solution HF 5% jusqu&#39;à ce que la surface de silicium hydrophobe tourne (30 ~ 100 s). Rincer à l&#39;eau déminéralisée et sécher avec un pistolet à azote. </li><li> Passivation des défauts Calcul de l&#39;échantillon dans une chambre à vide équipé d&#39;une source de plasma d&#39;hydrogène à distance. Pomper à &lt;1E-4 Torr, de la chaleur jusqu&#39;à l&#39;échantillon jusqu&#39;à ~ 620 ° C, mettez l&#39;argon / écoulement du mélange d&#39;hydrogène (50:150 sccm), régler la pression de 50 à 100 mTorr, commencer à la source de plasma à 3,5 kW de la puissance micro-ondes et pour poursuivre le processus ~ 10 minutes. Éteindre le chauffage tout en maintaYi-ning le plasma pour un autre 10-15 min jusqu&#39;à la température tombe en dessous de 350 ° C avant de mettre le plasma hors tension et l&#39;arrêt de l&#39;écoulement de gaz. Décharger l&#39;échantillon lorsque la température est inférieure à 200 ° C. </li><li> Métallisation de cellules Métallisation des cellules est réalisée en une série de motifs photolithographique consécutive, le dépôt et la gravure du film d&#39;Al étapes qui sont décrites en détail dans 11. La cellule final ressemble indiqué dans la dernière diapositive de la ANIMATION 3. Une vue rapprochée de la cellule est métallisé montré dans la figure 1. </li><li> Mesurer EEQ de la cellule métallisé. </li></ol> 2. Fabrication de la nanoparticule plasmonique Ag (Animation 4) <ol><li> Sonnez de la surface de la cellule métallisée avec de l&#39;azote sec pour enlever la poussière et de charger l&#39;échantillon dans un évaporateur thermique contenant un bateau rempli de granules W Ag (0,3-0,5 g). Pomper la chambre de vaporisation à la pression de base de 2 ~ 3E-5 Torr. QCM programme avec des paramètres pour Ag: Densité 10,50et Z rapport 0,529. </li><li> Veiller à ce que l&#39;obturateur est fermé échantillon, éteindre le chauffe bateau W en marche et d&#39;augmenter le courant assez lentement pour éviter une augmentation de pression au-dessus 8E-5 Torr jusqu&#39;à granulés Ag fondre (comme on l&#39;observe à travers un point de vue-port). Après la pression se stabilise régler le courant au point de consigne correspondant le taux de dépôt Ag de 0,1-0,2 Å / s (à partir de calibrage) et ouvrir l&#39;obturateur pour démarrer le processus de dépôt. </li><li> Surveiller l&#39;épaisseur de film en croissance Ag utilisant QCM et fermer l&#39;obturateur lorsque l&#39;épaisseur de 14 nm est atteint. Laisser le bateau W refroidir pendant environ 15 min, de décharger l&#39;échantillon. Le film devrait être recuit pour former des nanoparticules dès après le dépôt que possible pour éviter l&#39;oxydation Ag. </li><li> Une cellule d&#39;un film fraîchement déposée Ag est placée dans un four préchauffé purgé à l&#39;azote à 230 ° C 0.1 à 0.2, recuit pendant 50 min, puis déchargée. Notez le changement dans l&#39;aspect de surface due à des nanoparticules. Image en microscopie électronique à balayage de nanoparticules Ag est shown dans la Fig. 2. </li><li> Mesurer EEQ de la cellule avec le tableau nanoparticule. </li></ol> 3. Fabrication du réflecteur arrière Le réflecteur arrière se compose d&#39;environ 300 nm d&#39;épaisseur MgF 2 (RI 1,38) revêtement diélectrique d&#39;une couche d&#39;une peinture plafond blanc commerciale (Dulux). <ol><li> Avant de fabriquer le réflecteur arrière des contacts de cellules doivent être protégés par application d&#39;une encre noire marqueur sur eux, ce qui permet d&#39;exposer les contacts de sous le diélectrique par un procédé lift-off. </li><li> Utilisez pistolet à azote à souffler de l&#39;échantillon avec le tableau NP et des contacts peints pour les dépoussiérer. Utiliser une pression d&#39;azote modeste et faire preuve de prudence pour ne pas souffler les nanoparticules de suite. Placer l&#39;échantillon dans le vaporisateur thermique contenant un bateau W rempli de MgF 2 morceaux. Pomper l&#39;évaporateur à une pression de 2 ~ 3E-5 Torr. Définissez les paramètres QCM pour MgF 2: Densité 3,05 et ratio Z 0,637. </li><li> Veiller à ce que l&#39;échantillon Shutter est fermée, allumer le chauffe-bateau et augmenter lentement le courant pour éviter une augmentation de pression excessive jusqu&#39;à ce MgF 2 fond comme on le voit à travers un point de vue-port. Après la pression se stabilise régler le courant au point de consigne correspondant au taux de dépôt MgF 2 de 0,3 nm / s et d&#39;ouvrir l&#39;obturateur de l&#39;échantillon. </li><li> Surveiller l&#39;épaisseur déposée en utilisant QCM et fermer l&#39;obturateur lorsque 300 Nm est atteint. </li><li> Éteignez le chauffe. Laisser le bateau W à refroidir pendant environ 15 min, de décharger l&#39;échantillon. Noter la modification de l&#39;aspect de cellules avec le MgF 2 gaine. </li><li> À retirer le masque de l&#39;encre depuis les contacts de cellules immerger la cellule avec le diélectrique de gainage dans de l&#39;acétone. Attendre jusqu&#39;à ce que le diélectrique au-dessus de l&#39;encre commence la fissuration et un décollement. Garder la cellule dans l&#39;acétone jusqu&#39;à ce que tous l&#39;encre avec le diélectrique est enlevée et les contacts métalliques sont entièrement exposée. Retirer l&#39;échantillon de l&#39;acétone, rincez avec de l&#39;acétone fraîche et séchez-le avec des armes à feu d&#39;azote. </li><li> Appliquer une couche d&#39;unpeinture blanche (peinture Dulux plafond en une seule couche) avec un pinceau fin en douceur sur la surface de la cellule entière en évitant soigneusement les contacts métalliques. La couche de peinture doit être suffisamment épais pour être totalement opaque (~&gt; 0,5 mm), de sorte qu&#39;aucune lumière ne puisse être vu en regardant à travers la cellule peinte à la source lumineuse. Laissez la peinture sécher pendant une journée. </li><li> Mesurer EEQ de la cellule avec le réflecteur arrière peinture blanche. </li></ol> 4. Les résultats représentatifs La cellule solaire de court-circuit est calculée en intégrant la courbe EEQ sur le spectre solaire standard globale (masse d&#39;air 1.5). Tant la cellule courante et sa mise en valeur due à la lumière de piégeage dépend de l&#39;épaisseur couche de cellules d&#39;absorption: le courant lui-même est plus élevé pour les plus épaisses des cellules, mais la mise en valeur actuelle est supérieure pour les plus minces appareils, voir le tableau 1 pour les données respectives et animation de 5 pour EEQ courbes. Les 2 cellules d&#39;origine um d&#39;épaisseur, sans la lumière de piégeage, hav Jsc mesurée à l&#39;étape 1.7.) de ~ 15 mA / cm 2. Après la fabrication d&#39;un tableau nanoparticule, Jsc augmente jusqu&#39;à environ 20 mA / cm 2, qui est mise en valeur 32%. Il est légèrement meilleure que l&#39;effet d&#39;amélioration de 25-30% par le réflecteur arrière diffuse seulement. Après avoir ajouté le réflecteur arrière diffuse sur le MgF 2 de revêtement à la cellule avec le tableau des nanoparticules plasmonique, la JSC est encore augmenté à 22,3 mA / cm 2, ou l&#39;amélioration d&#39;environ 45%. Notez que pour la cellule 3 um d&#39;épaisseur tous les courants sont plus élevés, jusqu&#39;à 25,7 mA / cm 2, tandis que l&#39;amélioration relative est légèrement inférieur, 42%: la lumière de piégeage a un effet relativement plus importante dans les plus minces appareils. <table border="1"><tbody><tr><td> Épaisseur de la cellule: </td><td colspan="2"> 2 um </td><td colspan="2"> 3 um </td></tr><tr><td></td><td> Jsc, mA / cm 2 </td><td><s<html> trong&gt; +% </td><td> Jsc, mA / cm 2 </td><td> +% </td></tr><tr><td> cellule d&#39;origine </td><td> 15,4 </td><td></td><td> 18,1 </td><td></td></tr><tr><td> Réflecteur diffus arrière (R) </td><td> 20,1 </td><td> 30,5 </td><td> 21,5 </td><td> 18,8 </td></tr><tr><td> Nanoparticules (NP) </td><td> 20,3 </td><td> 31,8 </td><td> 21,9 </td><td> 21,0 </td></tr><tr><td> NP / MgF 2 / R </td><td> 22,3 </td><td> 45,3 </td><td> 25,7 </td><td> 42,0 </td></tr></tbody></table> Tableau 1. Plasmonique cellule de court-circuit et de son amélioration par rapport à la cellule d&#39;origine. <img alt="Figure 1" src="/files/ftp_upload/4092/4092fig1.jpg" /> Figure 1. Close-up vue de poly-Si la cellule solaire à film mince avec grille de métallisation. / Ftp_upload/4092/4092fig2.jpg &quot;/&gt; Figure 2. Image en microscopie électronique à balayage de nanoparticules Ag sur la surface de silicium. <img alt="Figure 3" src="/files/ftp_upload/4092/4092fig3.jpg" /> Figure 3. Une vue schématique d&#39;un silicium à couche mince plasmonique cristallin cellule solaire (pas à l&#39;échelle). <img alt="Figure 4" src="/files/ftp_upload/4092/4092fig4.jpg" /> Figure 4 rendement quantique externe et de court-circuit pour les silicium polycristallin cellules à couche mince avec réflecteur diffus et nanoparticules plasmoniques: pointillés noir - 2 originaux um d&#39;épaisseur cellule sans lumière de piégeage, Jsc 15,36 mA / cm 2, le bleu - la cellule. avec réflecteur peinture diffuse, Jsc 20,08 mA / cm 2; rouge - cellule avec des nanoparticules Ag plasmoniques, Jsc 20,31 mA / cm 2; vert - cellule avec des nanoparticules, MgF 2, et le réflecteur peinture diffuse, Jsc </em&gt; 22,32 mA / cm 2. Purple - 3 cellules um d&#39;épaisseur (le 3 de verre d&#39;épaisseur mm) avec des nanoparticules, MgF 2, et le réflecteur diffus, Jsc 25,7 mA / cm 2 (noter de réponse plus faible bleue due à des différences non intentionnelles dans les couches AR et l&#39;épaisseur émetteur). Solide noir - 2 pm cellulaire épaisse texture préparé par plasma de dépôt chimique en phase vapeur (sur verre de 3 mm d&#39;épaisseur), Jsc 26,4 mA / cm 2, à titre de comparaison. Animation 1. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation1.pptx" target="_blank">Cliquez ici pour voir l&#39;animation</a> . Animation 2. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation2.pptx" target="_blank">Cliquez ici pour voir l&#39;animation</a> . Animation 3. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation3.pptx" target="_blank">Cliquez ici pour voir l&#39;animation</a>. Animation 4. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation4.pptx" target="_blank">Cliquez ici pour voir l&#39;animation</a> . Animation 5. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation5.pptx" target="_blank">Cliquez ici pour voir l&#39;animation</a> .

<ol>
	<li>Henley, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kerf-free+wafering.">Kerf-free wafering.</a> , 1184-1192 (2010).</li><li>Kunz, O., Wong, J., Janssens, J., Bauer, J., Breitenstein, O., Aberle, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shunting+problems+due+to+sub-micron+pinholes+in+evaporated+solid-phase+crystallised+poly-Si+thin-film+solar+cells+on+glass.">Shunting problems due to sub-micron pinholes in evaporated solid-phase crystallised poly-Si thin-film solar cells on glass.</a> Progress Photovoilt.: Res. Appl. 17, 35-46 (2009).</li><li>Kunz, O., Ouyang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=5%+Efficient+evaporated+solid-phase+crystallised+polycrystalline+silicon+solar+cells.">5% Efficient evaporated solid-phase crystallised polycrystalline silicon solar cells.</a> Progress Photovolt.: Res. Appl. 17, 567-573 (2009).</li><li>Van Nieuwenhuysen, K., Payo, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epitaxially+grown+emitters+for+thin+film+silicon+solar+cells+result+in+16%+efficiency.">Epitaxially grown emitters for thin film silicon solar cells result in 16% efficiency.</a> Thin Solid Films. 518, S80-S82 (2008).</li><li>Lee, B. G., Stradin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light-trapping+by+a+dielectric+nanoparticle+back+reflector+in+film+silicon+solar+cells.">Light-trapping by a dielectric nanoparticle back reflector in film silicon solar cells.</a> Appl. Phys. Lett. 99, 064101 (2011).</li><li>Catchpole, K. R., Polman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasmonic+solar+cells.">Plasmonic solar cells.</a> Optics Express. 16, 21793-21800 (2008).</li><li>Ouyang, Z., Zhao, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoparticle+enhanced+light-trapping+in+thin-film+silicon+solar+cells.">Nanoparticle enhanced light-trapping in thin-film silicon solar cells.</a> Progress Photovolt.: Res. Appl. 19, 917-926 (2011).</li><li>Catchpole, K. R., Polman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+principle+for+particle+plasmon+enhanced+solar+cells.">Design principle for particle plasmon enhanced solar cells.</a> Appl. Phys. Lett. 93, 191113 (2008).</li><li>Beck, F. J., Mokkapati, S., Polman, A., Catchpole, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asymmetry+in+photocurrent+enhancement+by+plasmonic+nanoparticle+arrays+located+on+the+front+or+on+the+rear+of+solar+cells.">Asymmetry in photocurrent enhancement by plasmonic nanoparticle arrays located on the front or on the rear of solar cells.</a> Appl. Phys. Lett. 96, 033113 (2008).</li><li>Beck, F. J., Verhagen, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resonant+SPP+modes+supported+bt+discrete+metal+nanoparticles+on+high+index+substrates.">Resonant SPP modes supported bt discrete metal nanoparticles on high index substrates.</a> Optics Express. 19, 146-156 (2010).</li><li>Kunz, O., Ouyang, Z., al, a. t. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=5%+Efficient+evaporated+solid-phase+crystallised+polycrystalline+silicon+thin-film+solar+cells.">5% Efficient evaporated solid-phase crystallised polycrystalline silicon thin-film solar cells.</a> Progress Photovolt. 17, 567-573 (2009).</li><li>Keevers, M. J., Young, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=10%+Efficient+CSG+minimodules.">10% Efficient CSG minimodules.</a> , 1783-1790 (2007).</li></ol>

Pas de conflits d&#39;intérêt déclarés.

Évaporés cellules de silicium polycristallines et les nanoparticules diffusion de la lumière plasmonique sont des partenaires idéaux pour la lumière-piégeage. Ces cellules sont planes, ils ne peuvent donc pas compter sur une diffusion de lumière à partir de surfaces texturées, ni nanoparticules plasmoniques être facilement formé sur les surfaces texturées. Les cellules ont un seul, face arrière avec le silicium directement exposés, qui se trouve être également le meilleur emplacement pour la plupart des ...

<table border="1"><tbody><tr><td> Nom du réactif </td><td> Entreprise </td><td> Numéro de catalogue </td><td> Commentaires </td></tr><tr><td> Granulaire Argent </td><td> Sigma-Aldrich </td><td> 303372 </td><td> 99,99% </td></tr><tr><td> MgF 2, cristaux aléatoires, de qualité optique </td><td> Sigma-Aldrich </td><td> 378836 </td><td> &gt; = 99,99% </td></tr><tr><td> Peinture Dulux plafond en une seule couche </td><td> Dulux </td><td></td><td> R&gt; 90% (500-1100 nm) </td></tr></tbody></table>

polycrystalline silicon thin-film solar cells with plasmonic-enhanced light-trapping

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To compensate for lower light absorption such physically thin devices have to incorporate light-trapping which increases their optical thickness. Light scattering by textured surfaces is a common technique but it cannot be universally applied to all solar cell technologies. Some cells, for example those made of evaporated silicon, are planar as produced and they require an alternative light-trapping means suitable for planar devices. Metal nanoparticles formed on planar silicon cell surface and capable of light scattering due to surface plasmon resonance is an effective approach.
The paper presents a fabrication procedure of evaporated polycrystalline silicon solar cells with plasmonic light-trapping and demonstrates how the cell quantum efficiency improves due to presence of metal nanoparticles.
To fabricate the cells a film consisting of alternative boron and phosphorous doped silicon layers is deposited on glass substrate by electron beam evaporation. An Initially amorphous film is crystallised and electronic defects are mitigated by annealing and hydrogen passivation. Metal grid contacts are applied to the layers of opposite polarity to extract electricity generated by the cell. Typically, such a ~2 &mu;m thick cell has a short-circuit current density (Jsc) of 14-16 mA/cm2, which can be increased up to 17-18 mA/cm2 (~25% higher) after application of a simple diffuse back reflector made of a white paint.
To implement plasmonic light-trapping a silver nanoparticle array is formed on the metallised cell silicon surface. A precursor silver film is deposited on the cell by thermal evaporation and annealed at 23&deg;C to form silver nanoparticles. Nanoparticle size and coverage, which affect plasmonic light-scattering, can be tuned for enhanced cell performance by varying the precursor film thickness and its annealing conditions. An optimised nanoparticle array alone results in cell Jsc enhancement of about 28%, similar to the effect of the diffuse reflector. The photocurrent can be further increased by coating the nanoparticles by a low refractive index dielectric, like MgF2, and applying the diffused reflector. The complete plasmonic cell structure comprises the polycrystalline silicon film, a silver nanoparticle array, a layer of MgF2, and a diffuse reflector. The Jsc for such cell is 21-23 mA/cm2, up to 45% higher than Jsc of the original cell without light-trapping or ~25% higher than Jsc for the cell with the diffuse reflector only.
Introduction
Light-trapping in silicon solar cells is commonly achieved via light scattering at textured interfaces. Scattered light travels through a cell at oblique angles for a longer distance and when such angles exceed the critical angle at the cell interfaces the light is permanently trapped in the cell by total internal reflection (Animation 1: Light-trapping). Although this scheme works well for most solar cells, there are developing technologies where ultra-thin Si layers are produced planar (e.g. layer-transfer technologies and epitaxial c-Si layers) 1 and or when such layers are not compatible with textures substrates (e.g. evaporated silicon) 2. For such originally planar Si layer alternative light trapping approaches, such as diffuse white paint reflector 3, silicon plasma texturing 4 or high refractive index nanoparticle reflector 5 have been suggested.
Metal nanoparticles can effectively scatter incident light into a higher refractive index material, like silicon, due to the surface plasmon resonance effect 6. They also can be easily formed on the planar silicon cell surface thus offering a light-trapping approach alternative to texturing. For a nanoparticle located at the air-silicon interface the scattered light fraction coupled into silicon exceeds 95% and a large faction of that light is scattered at angles above critical providing nearly ideal light-trapping condition (Animation 2: Plasmons on NP). The resonance can be tuned to the wavelength region, which is most important for a particular cell material and design, by varying the nanoparticle average size, surface coverage and local dielectric environment 6,7. Theoretical design principles of plasmonic nanoparticle solar cells have been suggested 8. In practice, Ag nanoparticle array is an ideal light-trapping partner for poly-Si thin-film solar cells because most of these design principle are naturally met. The simplest way of forming nanoparticles by thermal annealing of a thin precursor Ag film results in a random array with a relatively wide size and shape distribution, which is particularly suitable for light-trapping because such an array has a wide resonance peak, covering the wavelength range of 700-900 nm, important for poly-Si solar cell performance. The nanoparticle array can only be located on the rear poly-Si cell surface thus avoiding destructive interference between incident and scattered light which occurs for front-located nanoparticles 9. Moreover, poly-Si thin-film cells do not requires a passivating layer and the flat base-shaped nanoparticles (that naturally result from thermal annealing of a metal film) can be directly placed on silicon further increases plasmonic scattering efficiency due to surface plasmon-polariton resonance 10.
The cell with the plasmonic nanoparticle array as described above can have a photocurrent about 28% higher than the original cell. However, the array still transmits a significant amount of light which escapes through the rear of the cell and does not contribute into the current. This loss can be mitigated by adding a rear reflector to allow catching transmitted light and re-directing it back to the cell. Providing sufficient distance between the reflector and the nanoparticles (a few hundred nanometers) the reflected light will then experience one more plasmonic scattering event while passing through the nanoparticle array on re-entering the cell and the reflector itself can be made diffuse - both effects further facilitating light scattering and hence light-trapping. Importantly, the Ag nanoparticles have to be encapsulated with an inert and low refractive index dielectric, like MgF2 or SiO2, from the rear reflector to avoid mechanical and chemical damage 7. Low refractive index for this cladding layer is required to maintain a high coupling fraction into silicon and larger scattering angles, which are ensured by the high optical contrast between the media on both sides of the nanoparticle, silicon and dielectric 6. The photocurrent of the plasmonic cell with the diffuse rear reflector can be up to 45% higher than the current of the original cell or up to 25% higher than the current of an equivalent cell with the diffuse reflector only.

Watch this Scientific Journal Video about Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping at JoVE.com

Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping

Base de silicium polycristallin en couches minces sur des cellules solaires en verre sont fabriqués par dépôt de couches de bore et de silicium dopé phosphore suivies par passivation défaut de cristallisation, et la métallisation. Plasmonique de blocage de lumière est introduit en formant nanoparticules Ag sur la surface cellulaire de silicium coiffé avec un réflecteur diffus résultant dans l&#39;amélioration de ~ 45% photocourant.

Base de silicium polycristallin à couche mince des cellules solaires avec plasmonique amélioré par Light-piégeage

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To ...

polycrystalline-silicon-thin-film-solar-cells-with-plasmonic-enhanced

Research

JoVE Journal

Engineering

18.7K vues.  University of New South Wales. Base de silicium polycristallin en couches minces sur des cellules solaires en verre sont fabriqués par dépôt de couches de bore et de silicium dopé phosphore suivies par passivation défaut de cristallisation, et la métallisation. Plasmonique de blocage de lumière est introduit en formant nanoparticules Ag sur la surface cellulaire de silicium coiffé avec un réflecteur diffus résultant dans l'amélioration de ~ 45% photocourant.

Vidéo: Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping

Nanomoulding of Functional Materials, a Versatile Complementary Pattern Replication Method to Nanoimprinting

We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding combined with layer transfer enables the replication of arbitrary surface patterns from a master structure onto the functional material. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes. In particular we demonstrate the fabrication of patterned transparent zinc oxide electrodes for light trapping applications in solar cells.

We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes.

Nanomoulding de matériaux fonctionnels, une méthode complémentaire de réplication Versatile Modèle de nano-impression

We describe a nanomoulding technique which  allows low-cost nanoscale patterning of functional materials, materials stacks  and full devices. Nanomoulding ...

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Ingénierie

Synthesis and Characterization of High c-axis ZnO Thin Film by Plasma Enhanced Chemical Vapor Deposition System and its UV Photodetector Application

In this study, zinc oxide (ZnO) thin films with high c-axis (0002) preferential orientation have been successfully and effectively synthesized onto silicon (Si) substrates via different synthesized temperatures by using plasma enhanced chemical vapor deposition (PECVD) system. The effects of different synthesized temperatures on the crystal structure, surface morphologies and optical properties have been investigated. The X-ray diffraction (XRD) patterns indicated that the intensity of (0002) diffraction peak became stronger with increasing synthesized temperature until 400 oC. The diffraction intensity of (0002) peak gradually became weaker accompanying with appearance of (10-10) diffraction peak as the synthesized temperature up to excess of 400 oC. The RT photoluminescence (PL) spectra exhibited a strong near-band-edge (NBE) emission observed at around 375 nm and a negligible deep-level (DL) emission located at around 575 nm under high c-axis ZnO thin films. Field emission scanning electron microscopy (FE-SEM) images revealed the homogeneous surface and with small grain size distribution. The ZnO thin films have also been synthesized onto glass substrates under the same parameters for measuring the transmittance.
For the purpose of ultraviolet (UV) photodetector application, the interdigitated platinum (Pt) thin film (thickness ~100 nm) fabricated via conventional optical lithography process and radio frequency (RF) magnetron sputtering. In order to reach Ohmic contact, the device was annealed in argon circumstances at 450 oC by rapid thermal annealing (RTA) system for 10 min. After the systematic measurements, the current-voltage (I-V) curve of photo and dark current and time-dependent photocurrent response results exhibited a good responsivity and reliability, indicating that the high c-axis ZnO thin film is a suitable sensing layer for UV photodetector application.

We offered a method to directly synthesize high c-axis (0002) ZnO thin film by plasma enhanced chemical vapor deposition. The as-synthesized ZnO thin film combined with Pt interdigitated electrode was used as sensing layer for ultraviolet photodetector, showing a high performance through a combination of its good responsivity and reliability.

Synthèse et caractérisation de l&#39;axe c Haute ZnO Thin Film par Plasma Enhanced Chemical Vapor Deposition système et son application Photodetector UV

In this study, zinc oxide (ZnO) thin films with high c-axis (0002) preferential orientation have been successfully and effectively synthesized onto ...

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly known as plasmonic effects, play an important role. Research in this field has, however, been impeded owing to the difficulty of fabricating devices containing the desired functional metal nanostructures. In order to provide a viable strategy to this issue, we herein show a transfer printing-based approach that allows the quick and low-cost integration of designed metal nanostructures with a variety of device architectures, including solar cells. Nanopillar poly(dimethylsiloxane) (PDMS) stamps were fabricated from a commercially available nanohole plastic film as a master mold. On this nanopatterned PDMS stamps, Ag films were deposited, which were then transfer-printed onto block copolymer (binding layer)-coated hydrogenated microcrystalline Si (&#181;c-Si:H) surface to afford ordered Ag nanodisk structures. It was confirmed that the resulting Ag nanodisk-incorporated &#181;c-Si:H solar cells show higher performances compared to a cell without the transfer-printed Ag nanodisks, thanks to plasmonic light trapping effect derived from the Ag nanodisks. Because of the simplicity and versatility, further device application would also be feasible thorough this approach.

A viable transfer printing-based methodology to introduce plasmonic metal nanostructures in solar cells is described. Using nanopillar poly(dimethylsiloxane) stamps, an Ag-based ordered nanodisk array was integrated with standard hydrogenated microcrystalline Si solar cells, which led to improved device performances due to plasmonic light trapping.

Intégration de la Lumière de piégeage argent Nanostructures dans hydrogénée microcristalline cellules solaires en silicium par impression par transfert

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly ...

Iridium Oxide-reduced Graphene Oxide Nanohybrid Thin Film Modified Screen-printed Electrodes as Disposable Electrochemical Paper Microfluidic pH Sensors

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use integrated paper microfluidic electrochemical pH sensor for resource-limited settings. Taking advantages from both pH meters and strips, the pH sensing platform is composed of hydrophobic barrier-patterned paper micropad (&#181;PAD) using polydimethylsiloxane (PDMS), screen-printed electrode (SPE) modified with IrO2-graphene films and molded acrylonitrile butadiene styrene (ABS) plastic holder. Repetitive cathodic potential cycling was employed for graphene oxide (GO) reduction which can completely remove electrochemically unstable oxygenated groups and generate a 2D defect-free homogeneous graphene thin film with excellent stability and electronic properties. A uniform and smooth IrO2 film in nanoscale grain size is anodically electrodeposited onto the graphene film, without any observable cracks. The resulting IrO2-RGO electrode showed slightly super-Nernstian responses from pH 2-12 in Britton-Robinson (B-R) buffers with good linearity, small hysteresis, low response time and reproducibility in different buffers, as well as low sensitivities to different interfering ionic species and dissolved oxygen. A simple portable digital pH meter is fabricated, whose signal is measured with a multimeter, using high input-impedance operational amplifier and consumer batteries. The pH values measured with the portable electrochemical paper-microfluidic pH sensors were consistent with those measured using a commercial laboratory pH meter with a glass electrode.

The study demonstrates the growth of iridium oxide-reduced graphene oxide (IrO2-RGO) nanohybrid thin films on irregular and rough screen-printed carbon substrate through a green electrochemical synthesis, and their implementation as a pH sensor with a patterned paper-fluidic platform.

Electrodes sérigraphiés oxyde d&#39;iridium réduite graphène Oxyde nanohybrides Thin Film modifié comme papier jetable Electrochemical microfluidiques pH Capteurs

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use ...

Digital Printing of Titanium Dioxide for Dye Sensitized Solar Cells

Silicon solar cell manufacturing is an expensive and high energy consuming process. In contrast, dye sensitized solar cell production is less environmentally damaging with lower processing temperatures presenting a viable and low cost alternative to conventional production. This paper further enhances these environmental credentials by evaluating the digital printing and therefore additive production route for these cells. This is achieved here by investigating the formation and performance of a metal oxide photoelectrode using nanoparticle sized titanium dioxide. An ink-jettable material was formulated, characterized and printed with a piezoelectric inkjet head to produce a 2.6 &#181;m thick layer. The resultant printed layer was fabricated into a functioning cell with an active area of 0.25 cm2 and a power conversion efficiency of 3.5%. The binder-free formulation resulted in a reduced processing temperature of 250 &#176;C, compatible with flexible polyamide substrates which are stable up to temperatures of 350 &#730;C. The authors are continuing to develop this process route by investigating inkjet printing of other layers within dye sensitized solar cells.

This paper investigates the suitability of inkjet printing for the manufacturing of dye-sensitized solar cells. A binder-free TiO2 nanoparticle ink was formulated and printed onto a FTO glass substrate. The printed layer was fabricated into a cell with an active area of 0.25 cm2 and an efficiency of 3.5%.

Impression numérique de dioxyde de titane pour les cellules solaires à colorant

Silicon solar cell manufacturing is an expensive and high energy consuming process. In contrast, dye sensitized solar cell production is less ...

Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity

A method for investigating recombination dynamics of photo-induced charge carriers in thin film semiconductors, specifically in photovoltaic materials such as organo-lead halide perovskites is presented. The perovskite film thickness and absorption coefficient are initially characterized by profilometry and UV-VIS absorption spectroscopy. Calibration of both laser power and cavity sensitivity is described in detail. A protocol for performing Flash-photolysis Time Resolved Microwave Conductivity (TRMC) experiments, a non-contact method of determining the conductivity of a material, is presented. A process for identifying the real and imaginary components of the complex conductivity by performing TRMC as a function of microwave frequency is given. Charge carrier dynamics are determined under different excitation regimes (including both power and wavelength). Techniques for distinguishing between direct and trap-mediated decay processes are presented and discussed. Results are modelled and interpreted with reference to a general kinetic model of photoinduced charge carriers in a semiconductor. The techniques described are applicable to a wide range of optoelectronic materials, including organic and inorganic photovoltaic materials, nanoparticles, and conducting/semiconducting thin films.

A Time Resolved Microwave Conductivity technique for investigating direct and trap-mediated recombination dynamics and determining carrier mobilities of thin film semiconductors is presented here.

Recombinaison Dynamics photovoltaïques en couches minces de matériaux par résolution temporelle Micro-ondes Conductivity

A method for investigating recombination dynamics of photo-induced charge carriers in thin film semiconductors, specifically in photovoltaic materials ...

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical properties. The possibility of doping was investigated by adding monovalent cation halides with similar ionic radii to Pb2+, including Cu+, Na+, and Ag+. A shift in the Fermi level and a remarkable decrease of sub-bandgap optical absorption, along with a lower energetic disorder in the perovskite, was achieved. An order-of-magnitude enhancement in the bulk hole mobility and a significant reduction of transport activation energy within an additive-based perovskite device was attained. The confluence of the aforementioned improved properties in the presence of these cations led to an enhancement in the photovoltaic parameters of the perovskite solar cell. An increase of 70 mV in open circuit voltage for AgI and a 2 mA/cm2 improvement in photocurrent density for NaI- and CuBr-based solar cells were achieved compared to the pristine device. Our work paves the way for further improvements in the optoelectronic quality of CH3NH3PbI3 perovskite and subsequent devices. It highlights a new avenue for investigations on the role of dopant impurities in crystallization and controls the electronic defect density in perovskite structures.

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells

Here, we present a protocol to adjust the properties of solution-processed CH3NH3PbI3 through the incorporation of monovalent cation additives in order to achieve highly efficient perovskite solar cells.

Monovalents Cation dopage du CH<sub&gt; 3</sub&gt; NH<sub&gt; 3</sub&gt; PbI<sub&gt; 3</sub&gt; Pour Efficient cellules solaires perovskite

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical ...

Electrospinning of Photocatalytic Electrodes for Dye-sensitized Solar Cells

This work demonstrates a protocol to fabricate a fiber-based photoanode for dye-sensitized solar cells, consisting of a light-scattering layer made of electrospun titanium dioxide nanofibers (TiO2-NFs) on top of a blocking layer made of commercially available titanium dioxide nanoparticles (TiO2-NPs). This is achieved by first electrospinning a solution of titanium (IV) butoxide, polyvinylpyrrolidone (PVP), and glacial acetic acid in ethanol to obtain composite PVP/TiO2 nanofibers. These are then calcined at 500 &#176;C to remove the PVP and to obtain pure anatase-phase titania nanofibers. This material is characterized using scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The photoanode is prepared by first creating a blocking layer through the deposition of a TiO2-NPs/terpineol slurry on a fluorine-doped tin oxide (FTO) glass slide using doctor blading techniques. A subsequent thermal treatment is performed at 500 &#176;C. Then, the light-scattering layer is formed by depositing a TiO2-NFs/terpineol slurry on the same slide, using the same technique, and calcinating again at 500 &#176;C. The performance of the photoanode is tested by fabricating a dye-sensitized solar cell and measuring its efficiency through J-V curves under a range of incident light densities, from 0.25-1 Sun.

The overall goal of this project was to use electrospinning to fabricate a photoanode with improved performance for dye-sensitized solar cells.

Electrospinification d&#39;électrodes photocatalytiques pour cellules solaires sensibilisées aux colorants

This work demonstrates a protocol to fabricate a fiber-based photoanode for dye-sensitized solar cells, consisting of a light-scattering layer made of ...

In Situ Monitoring of the Accelerated Performance Degradation of Solar Cells and Modules: A Case Study for Cu(In,Ga)Se2 Solar Cells

The levelized cost of electricity (LCOE) of photovoltaic (PV) systems is determined by, among other factors, the PV module reliability. Better prediction of degradation mechanisms and prevention of module field failure can consequently decrease investment risks as well as increase the electricity yield. An improved knowledge level can for these reasons significantly decrease the total costs of PV electricity. 
In order to better understand and minimize the degradation of PV modules, the occurring degradation mechanisms and conditions should be identified. This should preferably happen under combined stresses, since modules in the field are also simultaneously exposed to multiple stress factors. Therefore, two 'Combined Stress test with in situ measurement' setups have been designed and constructed. These setups allow the simultaneous use of humidity, temperature, illumination, and electrical biases as independently controlled stress factors on solar cells and minimodules. The setups also allow real-time monitoring of the electrical properties of these samples. This protocol presents these setups and describes the experimental possibilities. Moreover, results obtained with these setups are also presented: various examples about the influence of both deposition and degradation conditions on the stability of thin film Cu(In,Ga)Se2 (CIGS) as well as Cu2ZnSnSe4 (CZTS) solar cells are described. Results on the temperature dependency of CIGS solar cells are also presented.

In Situ Monitoring of the Accelerated Performance Degradation of Solar Cells and Modules: A Case Study for CuIn,GaSe2 Solar Cells

Two &#39;Combined Stress test with in situ measurement&#39; setups, which allow real-time monitoring of accelerated degradation of solar cells and modules, were designed and constructed. These setups allow the simultaneous use of humidity, temperature, electrical biases, and illumination as independently controlled stress factors. The setups and various experiments executed are presented.

In Situ Suivi de la dégradation de Performance accélérée des cellules et Modules solaires : une étude de cas pour les cellules solaires de Cu (In, Ga) Se2

The levelized cost of electricity (LCOE) of photovoltaic (PV) systems is determined by, among other factors, the PV module reliability. Better prediction ...

Bulk and Thin Film Synthesis of Compositionally Variant Entropy-stabilized Oxides

Here, we present a procedure for the synthesis of bulk and thin film multicomponent (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O (Co variant) and (Mg0.25(1-x)Co0.25(1-x)Ni0.25(1-x)CuxZn0.25(1-x))O (Cu variant) entropy-stabilized oxides. Phase pure and chemically homogeneous (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O (x = 0.20, 0.27, 0.33) and (Mg0.25(1-x)Co0.25(1-x)Ni0.25(1-x)CuxZn0.25(1-x))O (x = 0.11, 0.27) ceramic pellets are synthesized and used in the deposition of ultra-high quality, phase pure, single crystalline thin films of the target stoichiometry. A detailed methodology for the deposition of smooth, chemically homogeneous, entropy-stabilized oxide thin films by pulsed laser deposition on (001)-oriented MgO substrates is described. The phase and crystallinity of bulk and thin film materials are confirmed using X-ray diffraction. Composition and chemical homogeneity are confirmed by X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The surface topography of thin films is measured with scanning probe microscopy. The synthesis of high quality, single crystalline, entropy-stabilized oxide thin films enables the study of interface, size, strain, and disorder effects on the properties in this new class of highly disordered oxide materials.

The synthesis of high quality bulk and thin film (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O and (Mg0.25(1-x)Co0.25(1-x)Ni0.25(1-x)CuxZn0.25(1-x))O entropy-stabilized oxides is presented.

En vrac et la synthèse de minces d’oxydes d’entropie stabilisé une composition Variant

Here, we present a procedure for the synthesis of bulk and thin film multicomponent (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O (Co variant) and ...