Optical and carrier transport properties of graphene oxide based crystalline-Si/organic Schottky junction solar cells

Abstract

We investigated the graphene oxide (GO) based n-type crystalline silicon (c-Si)/conductive poly(ethylene dioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) Schottky junction devices with optical characterization and carrier transport measurement techniques. The optical transmittance in the UV region decreased markedly for the films with increasing the concentration of GO whereas it increased markedly in the visible-infrared regions. Spectroscopic ellipsometry revealed that the ordinary and extraordinary index of refraction increased with increasing the concentration of GO. The hole mobility also increased from 1.14 for pristine film to 1.85 cm2/V s for the 12–15 wt. % GO modified film with no significant increases of carrier concentration. The highest conductivity was found for a 15 wt. % GO modified PEDOT:PSS film: the c-Si/PEDOT:PSS:GO device using this sample exhibited a relatively high power conversion efficiency of 11.04%. In addition, the insertion of a 2–3 nm-thick GO thin layer at the c-Si/PEDOT:PSS interface suppressed the carrier recombination efficiency of dark electron and photo-generated hole at the anode, resulting in the increased photovoltaic performance. This study indicates that the GO can be good candidates for hole transporting layer of c-Si/PEDOT:PSS Schottky junction solar cell.

Optimization and Doping of Reduced Graphene Oxide–Silicon Solar Cells

“…21 GO has also been used as a buffer layer or filler material, or both, in systems that typically also contain PEDOT:PSS to great success. Liu et al 22 used a partially thermally reduced GO as a buffer layer between a Si substrate and a PEDOT:PSS:GO composite and achieved a PCE of 10%, while a 2.4 nm thick buffer layer of GO was used by Khatri et al 23 between a PEDOT:PSS:GO−Si interface for a PCE of 11%. GO can also be used to help suspend CNTs in aqueous solutions, with the resultant dispersion then filtered to produce CNT:GO−Si cells with a PCE of up to 6%.…”

“…To date, the application of solution-processed graphene that has not been chemically modified has seen little research in the G–Si field . There have been, however, a number of recent papers investigating GO– and rGO–Si heterojunctions. − Additionally, there have been several other works that use GO or rGO in some capacity in nanocarbon–silicon systems, whether as an intermediate layer between another carbon layer, such as the semiconducting polymer poly­(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS), , or as a surfactant for the suspension of CNTs to produce CNT:GO–Si cells …”

“…17 There have been, however, a number of recent papers investigating GO− and rGO−Si heterojunctions. 18−21 Additionally, there have been several other works that use GO or rGO in some capacity in nanocarbon−silicon systems, whether as an intermediate layer between another carbon layer, such as the semiconducting polymer poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS), 22,23 or as a surfactant for the suspension of CNTs to produce CNT:GO− Si cells. 24 The device architecture of rGO−Si solar cells is an important feature as the achievable power conversion efficiencies (PCEs) differ vastly between architectures.…”

Self-assembled silver nanowires as top electrode for poly(3,4-ethylenedioxythiophene):poly(stylenesulfonate)/n-silicon solar cell

“…Poly (3,4ethylenedioxythiophene):poly(stylenesulfonate) (PEDOT:PSS)/n-silicon hybrid solar cell has attracted great attention due to its high power conversion efficiency (η) and solution processing at low temperature [1][2][3][4][5][6][7][8][9][10][11][12][13]. Several approaches like: optimization of interfacial layer formation [5,6], three dimensional (3D)…”