Improving Carbon Nanotube‐Silicon Solar Cells by Solution Processable Metal Chlorides

Abstract

Carbon nanotube‐silicon (CNT‐Si) solar cells have the potential of being an alternative to the expensive crystal Si solar cells; however, there are critical limitations, such as the relatively low efficiency, instability, and lack of systematic improvement techniques. Herein, by investigating 17 solution processable, nonprecious metal chlorides, it is shown that appropriate chlorides can significantly improve the behavior of CNT‐Si solar cells individually or as mixtures. The results reveal a close relationship between the standard electrode potential of redox couples and the open‐circuit voltage (VOC) of solar cells, in which high VOC values are usually generated from chlorides with larger potentials. Detailed studies on SnCl2 and a mixture of FeCl3/ZrCl4 reveal mechanisms including doping of CNTs (increase in work function) and acting as antireflection layers, resulting in a substantial increase of both VOC and short‐circuit current density (JSC). As a result, stable power conversion efficiencies of 14.8% and 16.2% in CNT‐Si solar cells are achieved by simply spin‐coating SnCl2 or ZrCl4/FeCl3, respectively. The family of metal chlorides provide many opportunities for overcoming limitations and developing high‐performance CNT‐Si solar cells toward practical applications.

FeCl3-functionalized graphene oxide/single-wall carbon nanotube/silicon heterojunction solar cells with an efficiency of 17.5%

“…Electrochemical impedance spectroscopy (EIS) measurements were performed to evaluate carrier recombination at the SWCNT/Si interface. 14,36 As shown in Fig. 5f, all the curves are near semicircles, which suggests that there is only a single junction at the interface.…”

“…However, the FeCl 3 doping significantly improved the conductivity of the hybrid film. It is well known that metal chlorides can functionalize both SWCNTs 14 and GO films. 23 We also compared the I – V curves of FeCl 3 –SWCNT and FeCl 3 –GO–SWCNT films.…”

“…As a result several methods, including SWCNT film doping, the introduction of antireflection layers, and device structure optimization have been developed to improve the power conversion efficiency (PCE) of these cells. 1,11–14 For example, combining a SWCNT film with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), 15 Nafion, 12,16–18 or MoOx 1 has proved effective in improving both the carrier transfer and light absorption.…”

溶液法制备硅/SnCl2处理的Ti3C2TxMXene肖特基结 太阳电池

“…It is evident that both the minimum and maximum minority carrier lifetimes are increased for the SnCl 2 -treated case with an average τ of 59.0 μs, much longer than the corresponding value of 27.3 μs for the control case. Because these samples have the similar bulk lifetimes and wafer thicknesses, the prolonged τ together with the increased R rec thus well indicates the suppressed recombination for carriers at the interface between the Ti 3 C 2 T x MXene layer and n-Si substrate [58].…”

Front and Back‐Junction Carbon Nanotube‐Silicon Solar Cells with an Industrial Architecture

“…[ 2–6 ] With this architecture device power conversion efficiency (PCE) has steadily increased over the past decade from the preliminary work of Wei et al, [ 7 ] who reported 1.4% for a 0.49 cm 2 active area, to works from Jia et al, [ 2 ] Shi et al, [ 8 ] and the team around Maruyama, [ 9 ] reporting 13.8%, 15.1%, and 14.1%, respectively, for ≈0.01 cm 2 active areas. Notably, in 2014 Wang et al [ 10 ] reported a power conversion efficiency of 17% but over an area of 0.008 cm 2 , and in 2019 Wu et al [ 11 ] achieved 16.2% for 0.81 cm 2 . In our most recent work, we communicated the obtainment of 17.2% and 15.5% for 1 and 5 cm 2 active areas, respectively.…”