TiO2-Coated Carbon Nanotube-Silicon Solar Cells with Efficiency of 15%

Abstract

Combining carbon nanotubes (CNTs), graphene or conducting polymers with conventional silicon wafers leads to promising solar cell architectures with rapidly improved power conversion efficiency until recently. Here, we report CNT-Si junction solar cells with efficiencies reaching 15% by coating a TiO2 antireflection layer and doping CNTs with oxidative chemicals, under air mass (AM 1.5) illumination at a calibrated intensity of 100 mW/cm2 and an active device area of 15 mm2. The TiO2 layer significantly inhibits light reflectance from the Si surface, resulting in much enhanced short-circuit current (by 30%) and external quantum efficiency. Our method is simple, well-controlled, and very effective in boosting the performance of CNT-Si solar cells.

Carbon nanotubes for organic/inorganic hybrid solar cells

“…CNT-Si junction 15 mm 2 area solar cells with efficiencies reaching 15% is reported in Ref. [125]. Such high efficiency has been achieved by coating a TiO 2 antireflection layer and doping CNTs with oxidative chemicals under AM 1.5 illumination.…”

Implementation of antireflection layers for improved efficiency of carbon nanotube–silicon heterojunction solar cells

“…Recently, work focusing on using another polymer layer, poly(methyl methacrylate) (PMMA) acting as a broad band antireflection layer over Si-CNT solar cells was conducted and PCE was improved from 7.1 % to 11.5 % by increasing light trapping efficiency [16]. Some of the best Si-CNT solar cells to date have a PCE of 15 %, using a titanium dioxide antireflection layer and doping of the CNT film with oxidative chemicals (HNO 3 and H 2 O 2 ) [17]. More recent work has reported has reported efficiencies of 17 % [18].…”

“…It is worth noting that this was achieved with a much smaller active area than is common in the field and as such, the work by Shi is likely a better efficiency benchmark. [17] Here, we systematically explore polymer antireflection layer-related approaches that can improve the performance of Si-CNT devices, structured as shown in Figure 1. Specifically, three kinds of polymers including PDMS, PMMA and poly(styrene) (PS) have been …”

Electrical transport properties of isolated carbon nanotube/Si heterojunction Schottky diodes

“…4 Recently, a high performance CNT/Si solar cell with power conversion efficiency of 15% has been reported. 5 This device is ready for integrating the existing Si solar cells which hold a dominant share of the market and an even higher efficiency could be achieved by fabricating multi-junction solar cells. The CNT/Si heterojunction has attracted great interest not only for solar cells [5][6][7] , but also for photodetectors [8][9][10] in the wide wavelength ranging from ultraviolet to near-infrared.…”

“…In addition, multiple electron-hole pairs associated with the higher subbands at low temperatures could enhance the device performance. 11 While the SWNT/Si heterojunction could play a crucial role in the CNT based devices, the measurements of electrical transport properties on the heterojunctions between isolated SWNT and Si have yet not been made because most of the work has been done by using CNT composite film 5,6,10 or multiwalled CNTs. 8,9 Figure 1 shows an outline of the CNT/Si diode fabrication process.…”