Investigating the Effect of Carbon Nanotube Diameter and Wall Number in Carbon Nanotube/Silicon Heterojunction Solar Cells

Abstract

Suspensions of single-walled, double-walled and multi-walled carbon nanotubes (CNTs) were generated in the same solvent at similar concentrations. Films were fabricated from these suspensions and used in carbon nanotube/silicon heterojunction solar cells and their properties were compared with reference to the number of walls in the nanotube samples. It was found that single-walled nanotubes generally produced more favorable results; however, the double and multi-walled nanotube films used in this study yielded cells with higher open circuit voltages. It was also determined that post fabrication treatments applied to the nanotube films have a lesser effect on multi-walled nanotubes than on the other two types.

Direct‐Patterning SWCNTs Using Dip Pen Nanolithography for SWCNT/Silicon Solar Cells

“…Preparation of Solar Cells : The method of fabricating the SWCNT/Si solar cells is based on previous work by Yu et al (see Figure a) . The n‐type phosphorous‐doped silicon substrate with 100 nm oxide layer was spin coated (30 s, 3000 rpm) with positive photoresist (methoxypropyl acetate) and then soft baked (1 min, 100 °C).…”

“…CNT films are cheaper, and quicker to manufacture, have much greater flexibility, and have excellent charge carrier mobility (exceeding 10 5 cm 2 V −1 s −1 for individual CNTs at room temperature) . CNT films also still retain high solar spectrum transmittance, good stability under heat and light exposure, low light reflectance, low resistivity (electrical conductivity 10 4 –10 6 S cm −1 ), and tuneable light absorption properties . These properties make CNT films a desirable material to use as the p‐type layer (majority hole carrier) in solar cells.…”

“…The first CNT/Si cell reported was by Wei et al in 2007 and since then, different methods of manufacturing and applying the CNT film, and different compositions and treatments of the CNT film have been investigated. Improvements to the design of CNT/Si cells have increased their power conversion efficiency (PCE) including doping of the CNT film with an electron withdrawing/p‐doping chemical/nanoparticle/nanowire, using single‐walled and metallic or (6,5) semiconducting CNTs, creating a 1–2 nm Si oxide layer or a thin conductive polymer layer between the n‐type Si and the CNT film, using an antireflective layer, using a thinner n‐type Si layer, using an aligned CNT film, and optimizing the structure of the p‐type CNT film and front contact electrodes . Cells with PCE of up to 17% have been reported, which is becoming comparable to commercially available p–n silicon solar cells (20–30% PCE).…”

Nanostructured Solar Cells

“…In this issue, Jia and coworkers integrated aluminum nanoparticles on silicon solar cells, which facilitate light trapping and bring increased device performance [1]. Shapter’s group studied the effect of the size of carbon nanotubes on the performance of carbon nanotube/silicon heterojunction solar cells—a new concept in silicon solar cells [2]. In addition to single junction solar cells, nanostructures can also be utilized for tandem solar cells to enable current match between separated cells.…”

Single Wall Carbon Nanotubes Synthesis through Methane Chemical Vapor Deposition over MCM-41–Co Catalysts: Variables Optimization

“…This behavior is quite important when a material with a narrow band-gap value is required such as in the research of field-effect transistors [6]. Besides the semiconducting properties, SWCNTs present high electron and hole mobilities [7], improving short-circuit currents in solar cell devices [8,9]; through chemical doping of the graphitic structure, the band-gap is modified and permits the SWCNTs to serve as a chemical sensor where the response is generally interpreted as a current change when a probe molecule interacts with the doping agent in the graphitic structure [10]. Another important application field in gas adsorption, nanotube packaging leaves interstitial pores where small molecules such as hydrogen can be adsorbed for energy-related research [10].…”