Graphene as a transparent electrode for amorphous silicon-based solar cells

Abstract

The properties of graphene in terms of transparency and conductivity make it an ideal candidate to replace indium tin oxide (ITO) in a transparent conducting electrode. However, graphene is not always as good as ITO for some applications, due to a non-negligible absorption. For amorphous silicon photovoltaics, we have identified a useful case with a graphene-silica front electrode that improves upon ITO. For both electrode technologies, we simulate the weighted absorption in the active layer of planar amorphous silicon-based solar cells with a silver back-reflector. The graphene device shows a significantly increased absorbance compared to ITO-based cells for a large range of silicon thicknesses (34.4% versus 30.9% for a 300 nm thick silicon layer), and this result persists over a wide range of incidence angles.

HIT Solar Cell Modeling Using Graphene as a Transparent Conductive Layer Considering the Atacama Desert Solar Spectrum

“…When the light impinges on the back side, the current density reaches the highest value, J sc = 34.88 mA/cm 2 , for a donor concentration of 9.5 × 10 16 1/cm 3 (red circle in Figure A1a). When the light hits from the front, the J SC increases its value as the concentration of donors increases, and, in the modeling, it is not possible to infinitely increase the donors be-cause this leads to the Fermi energy level (E f ) being lower than the conduction energy E c in the c − Si shell, which is not possible [17]. However, if the carrier concentration is >0.4 × 10 17 1/cm 3 in the c − Si layer concentration, this corresponds to J sc = 34.86 mA/cm 2 .…”

“…With this configuration, the efficiency of the organic cell was 4.2%, which was lower compared to the use of ITO (6.1%) due to a higher sheet resistance. Graphene has also been studied for ITO and AZO replacement in HIT cells due to its high transparency (97% for the monolayer) [16,17]; for its sheet resistance, which is as low as 0.882 Ω/cm 2 [6]; and for its carrier mobility, which is over 7350 cm 2 /V•s [18][19][20]. Lancellotti et al [21] characterized the sheet resistance, varying the number of graphene layers between one and five, and with only four and five layers, they achieved AZO conductivity properties.…”

Graphene oxide decorated with gold enables efficient biophotovolatic cells incorporating photosystem I

“…[26][27][28][29][30] Nano-composites based on carbon allotropes such as graphene, graphene oxide (GO) and reduced graphene oxide (rGO) exhibit a similar combination of useful properties: high electrical conductivity, large surface area, mechanical exibility, good carrier mobility, thermal conductivity and transparency in the visible range of the spectrum. 7,11,21,[31][32][33] These materials have been used as chargetransfer layers in silicon-based solar cells, [34][35][36] dye-sensitized solar cells [37][38][39] and other energy storage devices. 27,[40][41][42] In previous studies, when PSI was deposited onto GO surfaces, the hydroxy (-OH), carboxylic acid (-COOH), and epoxide groups present in GO make it particularly well suited for PSI-based BPV devices because they interact selectively with PSI to affect the orientation of the hole-and electron-injecting sides with respect to the charge-transfer layers and electrodes.…”

Recent trends in preparation and application of carbon nanotube–graphene hybrid thin films

“…attractive materials for applications such as transparent electrodes [1][2][3][4][5], optoelectronics [6,7], field-effect transistors [8][9][10], energy storage materials [11][12][13], biosensors [14][15][16][17], and composites [18,19]. In recent years, combinations of one-dimensional (1D) carbon nanotubes (CNTs) and twodimensional (2D) graphene sheets to form flexible threedimensional (3D) CNT-graphene hybrid thin fims (CNGHTFs) have attracted great attention owing to their intriguing properties.…”