Este projeto de pesquisa apoiado pelo Conselho de Pesquisa australiano através da concessão de ligação com CSG Solar Pty. Ltd. Jing Rao reconhece a Universidade de NSW Fellowship Vice-Chanceler de Pós-Doutorado. MEV foram tiradas por Jongsung parque que usa o equipamento fornecido pela Unidade de Microscopia Eletrônica da Universidade de NSW.

1. Fabricação de células solares de silício policristalino (Animação 3) <ol><li> Silicon deposição de filmes <ol class="lalpha"><li> Preparar a ferramenta de evaporação de feixe-cozendo-o para fora a ~ 100 ° C durante a noite para atingir a pressão de base de &lt;Torr 3E-8. Aquecedor a predefinição de exemplo para os 150 ° C de temperatura de espera. </li><li> Use um substrato feito de 5x5 cm 2 (ou 10 x10 cm 2) substrato de borosilicato de vidro (Schott Borofloat33), 1,1 ou 3,3 mm de espessura, revestido com ~ 80 nm de nitreto de silício (preparado por PECVD a partir de N 2 e mistura SiH 4). </li><li> Soprar a superfície do substrato com azoto seco para remover a poeira e colocá-lo em um suporte de amostra. Ventilar o bloqueio de carga, carregar a amostra, bombear a carga bloquear à pressão &lt;Torr 1E5, e transferir a amostra para a câmara principal. Iniciar o aquecimento para o ponto de ajuste de 250 ° C. Bombear para cerca de 20 min, quando a pressão atinge-8E 8 Torr ou menos. </li><li> Verificar se o dopanteobturadores fonte de origem e de o silício está fechado. Predefinidos temperaturas fonte dopante, para temperaturas de espera, ou seja, a temperatura da fonte de fósforo a 700 ° C e temperatura da fonte de boro a 1250 ° C. Iniciar e arma-e derreter o silício em um cadinho por aumentar lentamente a corrente e-gun. </li><li> Quando a corrente necessária é alcançada (a partir da calibração anterior: esta corrente pode variar dependendo do e-gun e as condições fonte de Si) evaporar camadas de silício dopado com as necessárias concentrações de P e B: 35 nm emissor em 1E20 cm -3 de P ; 2 ~ absorvedor iM 3 a 5E15 -3 cm de B; 100 nm campo de volta à superfície (BSF) com 4E19 -3 cm de B. As concentrações exactas dopantes são conseguidos combinando as taxas de deposição certos Si, como medido por quartzo de cristal do Monitor (QCM), com certas temperaturas fonte dopantes, utilizando relações estabelecidas a partir da calibração SIMS. </li><li> Após a evaporação é feito mudar o aquecedor desligado, esfriar a amostra para ~ 10 min. Transfer a amostra para a carga de bloqueio, fechar a válvula de gaveta, ventilar o bloqueio de carga e descarga da amostra com a película de silicone. </li></ol></li><li> Silicon cristalização Se a amostra é 10x10 cm 2, ele pode ser cortado em quatro 5x5 cm 2 pedaços de tamanho de células antes da cristalização. Coloque um filme de silício depositados sobre vidro (Si película acima) em um suporte feito de rugosa e nitreto de silício revestido Schott Robax vidro (para evitar a aderência). Carga em uma estufa de azoto pré-aquecido a purgado 200-300 ° C. Rampa até a temperatura até 600 ° C a 3 ~ 5 ° C / min e recozimento durante 30 hr. Ligue o aquecedor de forno e deixe forno arrefecer naturalmente até ~ 200 ° C (2 ~ 3 hr) antes da descarga da amostra. A amostra pode ter uma forma côncava devido ao encolhimento de silício durante a cristalização. Vai achatar durante o processamento rápido a seguir térmica. </li><li> Ativação dos dopantes e defeito de recozimento (RTA) Colocar a amostra com o filme cristalizou em um suporte feito de grafite pirolítica e load a um processador térmico rápido purgado com árgon. Rampa a temperatura até 600 ° C a 1 ° C / s, em seguida, até 1000 ° C a 20 ° C / s, mantenha durante 1 min, em seguida, arrefecer naturalmente até ~ 100 ° C e de descarregamento. </li><li> Remoção de óxido da superfície Imediatamente antes da hidrogenação do óxido de superfície formada em um filme de silício durante a cristalização e RTA deve ser removido para garantir que a superfície da película nua silício é exposta a hidrogénio. Mergulha-se o recozido amostra em 5% de solução de HF até que a superfície de silício transforma hidrofóbico (30 ~ 100 s). Enxágüe com água deionizada e seque com uma arma de nitrogênio. </li><li> Passivação Defeito Carregar a amostra em uma câmara de vácuo equipado com a fonte remota de hidrogénio plasma. Bombear até &lt;1E-4 Torr, aquecer a amostra até ~ 620 ° C, ligar o argônio / fluxo da mistura de hidrogênio (50:150 sccm), defina pressão 50-100 mTorr, comece a fonte de plasma de 3,5 kW de a potência de microondas e continuar o processo para ~ 10 min. Desligar o aquecedor enquanto maintaIning o plasma para um outro min 10-15 até que a temperatura cai abaixo de 350 ° C antes de ligar o plasma fora e parar o fluxo de gás. Descarregar a amostra quando a temperatura está abaixo de 200 ° C. </li><li> Metalização de células Metalização célula é conduzida de uma série de padrões fotolitográfico consecutivo, a deposição de filme Al e decapagem passos que são descritos em pormenor no 11. A célula final olha como mostrado no último slide da animação 3. Uma vista de perto da célula metalizada é mostrado na Fig. 1. </li><li> Medir EQE da célula metalizado. </li></ol> 2. Fabricação de nanopartículas Ag plasmonic (Animação 4) <ol><li> Soprar a superfície da célula metalizada com azoto seco para remover a poeira e carregar a amostra em um evaporador térmica contendo um barco W cheio com grânulos de Ag (0,3-0,5 g). Bombear para baixo da câmara de evaporador para a pressão base de 2 ~ 3E-5 Torr. QCM programa com parâmetros para Ag: Densidade 10,50e Z rácio 0,529. </li><li> Assegure-se que o obturador da amostra é fechada, ligar o aquecedor barco W sobre e aumentar a corrente lentamente o suficiente para evitar aumento de pressão acima 8E-5 Torr até derreter grânulos Ag (como observado por meio de uma vista de porta-). Após a pressão estabiliza definir o atual até o ponto de referência correspondente a taxa de deposição de Ag de 0,1-0,2 Å / s (a partir da calibração) e abrir o obturador para iniciar o processo de deposição. </li><li> Monitorar a espessura da película em crescimento Ag usando QCM e fechar o obturador quando a espessura de 14 nm é atingido. Permitir que o barco W esfriar por cerca de 15 min, retirar a amostra. A película deve ser recozido para formar nanopartículas logo após a deposição quanto possível para evitar a oxidação Ag. </li><li> Uma célula com um filme de Ag recém depositado é colocada num forno purgado com azoto pré-aquecido a 230 ° C 0,1-0,2, recozidas durante 50 min e, em seguida descarregado. Note-se a alteração na aparência da superfície, devido à nanopartículas. Digitalização de imagem de microscopia eletrônica de nanopartículas de Ag é shown na fig. 2. </li><li> Medir EQE da célula com a matriz de nanopartículas. </li></ol> 3. Fabricação do refletor traseiro O refletor traseiro é constituído de aproximadamente 300 nm de espessura MgF 2 (RI 1,38) revestimento dielétrico com um revestimento de uma tinta teto branco comercial (Dulux). <ol><li> Antes de fabricar o reflector traseiro dos contactos celulares têm de ser protegidos por aplicação de uma tinta de marcador preto sobre eles, o que permite expor os contactos do âmbito do dieléctrico por um processo de elevação-off. </li><li> Use uma pistola de nitrogênio para explodir a amostra com NP matriz e contatos pintados para remover a poeira. Use a pressão modesta nitrogênio e tenha cuidado para não fundir as nanopartículas de distância. Colocar a amostra para o evaporador térmica contendo um barco W preenchido com MgF 2 peças. Bombear o evaporador a uma pressão de 2 ~ Torr 3E-5. Definir parâmetros QCM para MgF 2: Densidade 3,05 e Z relação 0,637. </li><li> Certifique-se que a amostra shutter é fechada, ligar o aquecedor do barco e, lentamente, aumentar a corrente para evitar aumento de pressão excessiva até MgF 2 derrete como pode ser visto através de uma visão porta. Após a pressão estabiliza definir o atual até o ponto de referência correspondente a MgF taxa de deposição de 2 de 0,3 nm / s e abrir o obturador da amostra. </li><li> Monitorar a espessura depositados utilizando QCM e fechar o obturador quando 300 nm é atingido. </li><li> Desligue o aquecedor. Permitir que o barco W esfriar por cerca de 15 min, retirar a amostra. Note-se a alteração na aparência da célula com o revestimento 2 FGM. </li><li> Para remover a máscara de tinta a partir dos contactos celulares imergir a célula com o dieléctrico revestimento em acetona. Aguarde até que o dielétrico acima a tinta começa a rachar e levantando. Manter a célula em acetona até toda a tinta com o dieléctrico é removido e os contactos de metal são totalmente exposta. Retirar a amostra a partir de acetona, lavar com acetona fresca e seque com arma de nitrogênio. </li><li> Aplicar uma camada de umtinta branca (Dulux tinta tecto One Coat-) com um pincel fino macio na superfície da célula inteira evitando cuidadosamente os contactos de metal. A camada de tinta tem de ser suficientemente espessa para ser completamente opaca (~ mm&gt; 0,5), de modo que nenhuma luz pode ser visto quando se olha através da célula pintado na fonte de luz brilhante. Deixe a tinta secar por um dia. </li><li> Medir EQE da célula com o reflector branco tinta traseira. </li></ol> 4. Os resultados representativos A célula solar corrente de curto-circuito é calculada através da integração da curva EQE sobre o espectro padrão global solar (massa de ar de 1,5). Tanto a corrente da célula e do seu reforço devido à luz-aprisionamento de depender da espessura da camada de células de absorção: a corrente em si é mais elevada para as células mais espessas, mas o aumento de corrente é maior para os dispositivos mais finos, ver Tabela 1 para os respectivos dados e animação 5 para EQE curvas. Os originais 2 células mm de espessura, sem luz-caça com armadilhas, hav Jsc medido no passo 1.7.) de ~ 15 mA / cm 2. Após a fabricação de uma matriz de nanopartículas, JSC aumenta até cerca de 20 mA / cm 2, que é reforço 32%. É ligeiramente melhor do que o efeito de aumento de 25-30% pelo reflector traseira difusa só. Depois de adicionar o reflector traseira difusa no MgF 2 revestimento para a célula com a matriz de nanopartículas plasmonic, o Jsc é aumentada ainda mais para 22,3 mA / cm 2, ou o reforço de cerca de 45%. Note-se que para a célula iM 3 espessa todas as correntes são mais elevados, até 25,7 mA / cm 2, enquanto o aumento relativo é ligeiramente inferior, 42%: luz aprisionamento-tem um efeito relativamente maior em dispositivos mais finas. <table border="1"><tbody><tr><td> A espessura das células: </td><td colspan="2"> 2 micra </td><td colspan="2"> 3 mm </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> célula original </td><td> 15,4 </td><td></td><td> 18,1 </td><td></td></tr><tr><td> Refletor difuso traseiro (R) </td><td> 20,1 </td><td> 30,5 </td><td> 21,5 </td><td> 18,8 </td></tr><tr><td> As nanopartículas (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> Tabela 1. Plasmonic célula corrente de curto-circuito e seu reforço em comparação com célula original. <img alt="A Figura 1" src="/files/ftp_upload/4092/4092fig1.jpg" /> Figura 1. Vista Close-up de poli-Si células de película fina solar com grade de metalização. / Ftp_upload/4092/4092fig2.jpg &quot;/&gt; Figura 2. Scanning imagem de microscopia de electrões de nanopartículas de Ag na superfície de silício. <img alt="A Figura 3" src="/files/ftp_upload/4092/4092fig3.jpg" /> Figura 3. Uma vista esquemática de uma silício cristalino plasmonic película fina de células solares (não à escala). <img alt="A Figura 4" src="/files/ftp_upload/4092/4092fig4.jpg" /> Figura 4 eficiência quântica externa e de curto-circuito para os de silício policristalino película fina de células com refletor difuso e nanopartículas plasmonic: tracejada preta - original 2 mm de espessura cela sem luz-caça com armadilhas, Jsc 15,36 mA / cm 2, azul - célula. com refletor pintura difusa, Jsc 20,08 mA / cm 2; vermelho - célula com nanopartículas plasmonic Ag, Jsc 20,31 mA / cm 2; verde - celular com nanopartículas, MgF 2, e refletor pintura difusa, Jsc </em&gt; 22,32 mA / cm 2. Purple - 3 mm de espessura de células (em 3 de vidro mm de espessura) com nanopartículas, MgF 2, e reflector difusa, JSC 25,7 mA / cm 2 (notar menor resposta azul devido a diferenças não intencionais nas camadas AR ea espessura emissor). Sólido negro - 2 m de espessura célula texturizados preparado por plasma melhorada deposição de vapor químico (em 3 de vidro mm de espessura), JSC 26,4 mA / cm 2, mostrada para comparação. Animação 1. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation1.pptx" target="_blank">Clique aqui para ver a animação</a> . Animação 2. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation2.pptx" target="_blank">Clique aqui para ver a animação</a> . Animação 3. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation3.pptx" target="_blank">Clique aqui para ver a animação</a>. 4 Animação. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation4.pptx" target="_blank">Clique aqui para ver a animação</a> . Animação 5. <a href="http://www.jove.com/files/ftp_upload/4092/4092animation5.pptx" target="_blank">Clique aqui para ver a animação</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>

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Células solares de silício policristalino evaporado e as nanopartículas de dispersão da luz plasmônicos são os parceiros ideais para a luz-caça com armadilhas. Tais células são planas, portanto, eles não podem contar com espalhamento de luz a partir de superfícies texturizadas, nem pode ser facilmente plasmonic nanopartículas formadas em superfícies texturizadas. As células têm uma única superfície, traseira com silício diretamente exposta, o que também acontece a ser a melhor localização para a mai...

<table border="1"><tbody><tr><td> Nome do reagente </td><td> Companhia </td><td> Número de catálogo </td><td> Comentários </td></tr><tr><td> Granular Prata </td><td> Sigma-Aldrich </td><td> 303372 </td><td> 99,99% </td></tr><tr><td> MgF 2, os cristais aleatórios, grau óptico </td><td> Sigma-Aldrich </td><td> 378836 </td><td> &gt; = 99,99% </td></tr><tr><td> Dulux pintura teto de uma demão- </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

Silício policristalino de película fina de células solares em vidro são fabricados pela deposição de boro e fósforo camadas de silício dopado seguido por cristalização passivação defeito, e metalização. Plasmonic luz aprisionamento é introduzido através da formação de nanopartículas de Ag na superfície da célula de silício tapado com um reflector difusa resultando em ~ reforço fotocorrente 45%.

Silício policristalino de película fina de células solares com plasmonic avançada Luz-caça com armadilhas

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 visualizações.  University of New South Wales. Silício policristalino de película fina de células solares em vidro são fabricados pela deposição de boro e fósforo camadas de silício dopado seguido por cristalização passivação defeito, e metalização. Plasmonic luz aprisionamento é introduzido através da formação de nanopartículas de Ag na superfície da célula de silício tapado com um reflector difusa resultando em ~ reforço fotocorrente 45%.

Vídeo: 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 Materiais Funcionais, um método de replicação Versátil Complementar Padrão para nanoimpressão

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

Engenharia

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.

Síntese e Caracterização de alta c-eixo ZnO Thin Film por Plasma aprimorado Chemical Vapor Deposition Sistema e sua Aplicação 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.

Integração da luz Interceptação de prata Nanoestruturas em células solares de silício hidrogenado microcristalina por Transferência de impressão

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.

Grafeno Oxide Nanohybrid Thin Film eléctrodos modificados serigrafado reduzida de óxido de irídio como papel Electrochemical descartável microfluídicos pH Sensores

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%.

Impressão digital de dióxido de titânio para células solares Dye sensibilizados

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.

Recombinação Dynamics em Thin-film materiais fotovoltaicos via Condutividade Microondas resolvida no tempo

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.

Monovalente Cation Doping de CH<sub&gt; 3</sub&gt; NH<sub&gt; 3</sub&gt; PBI<sub&gt; 3</sub&gt; For eficientes células solares Perovskita

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.

Electrospinning de eletrodos fotocatalíticos para células solares sensibilizadas por corante

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 Monitoramento da degradação desempenho acelerado de células solares e módulos: um estudo de caso de Cu (In, Ga) Se2 células solares

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.

Granel e síntese de película fina de óxidos de entropia-estabilizado em termos de composição variantes

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 ...