Application of a hole transporting organic interlayer in graphene oxide/single walled carbon nanotube–silicon heterojunction solar cells

Abstract

An organic conductive polymer is used to improve charge transport and efficiency in carbon nanotube–silicon solar cells.

Application of Hole-Transporting Materials as the Interlayer in Graphene Oxide/Single-Wall Carbon Nanotube Silicon Heterojunction Solar Cells

“…This trend is because a better heterojunction is formed initially, with the increase in thickness providing decreased recombination at first, but when the film is very thick, the ability to transport holes collected from Si to the GOCNT electrode decreases. [24] In terms of the photocurrent, the general trend is that it decreases with increase in HTL thickness, as shown in Fig. 4d.…”

“…[54] For instance, AuCl 3 aqueous solution was applied to the device surface by spin-coating in our previous study. [24] Here, a new doping process in an acetone bath is developed (refer to Experimental details), which can be potentially applied to transfer any floating GOCNT or thick CNT films onto any substrates without damaging the surface. The detailed effects of the AuCl 3 doping on the performance of the solar cells (GOCNT/Si and GOCNT/HTL/Si with optimised HTL thickness) are summarised and plotted in Fig.…”

“…2c, and these values are similar to those of the GOCNT films in our previous studies. [24] A SWCNT network covered with and interspersed with GO sheets is observed in the SEM image of the as-prepared film (Fig. 2d), and can be contrasted with the wrinkle features in pure GO and the network structure in pure CNT film (Fig.…”

“…[21] A few studies have shown that the addition of an extra interlayer of conducting polymers, such as polyaniline, [22] poly(3-hexylthiophene-2,5-diyl) (P3HT), [23] and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), between Si and CNT can improve the performance of the CNT/Si devices. [23] Recently, 2,2 0 ,7,7 0 -tetrakis(N,N 0 -di-p-methoxyphenylamine)-9,9 0 -spirobiuorene (spiro-OMeTAD), which plays the same role in a GOCNT/Si solar cell, has successfully improved efficiency to above 13 % [24] owing to improved hole transport. [25][26][27] In addition to these traditional materials, there are also some recently synthesised new low-cost hole-transporting layer (HTL) materials, which have been successfully applied in perovskite solar cells, such as 4,4 0 -(naphthalene-2,6-diyl)bis(N, N-bis (4-methoxyphenyl)aniline) (NAP) [28] and (E)-4 0 ,4 000 -(ethene-1,2-diyl)bis(N,N-bis(4-methoxyphenyl)-[1 00 ,1 000 -biphenyl]-4-amine) (BPV) with comparable efficiency to that of spiroOMeTAD.…”

“…[ 24] The improvement of the performance is mainly due to the increased V OC . With the HTL, the devices have better diode properties with lower ideality and J sat and higher F B , which is used to estimate recombination, with lower values corresponding to more serious recombination, lower FF and V OC .…”