Methyl/Allyl Monolayer on Silicon: Efficient Surface Passivation for Silicon-Conjugated Polymer Hybrid Solar Cell

Abstract

We demonstrate a hybrid Schottky junction solar cell based on methyl/allyl groups terminated silicon nanowire arrays (SiNWs) and poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) with a power conversion efficiency (PCE) of 10.2%. The methyl/allyl organic monolayer on silicon can act as an excellent passivation layer for suppressing surface charge recombination, which is characterized by grazing angle attenuated total reflectance Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy measurements. The transient and steady electric output characteristics measurements indicate that the density of trap states of SiNWs are dramatically suppressed by methyl/allyl surface modification. In addition, the device based on methyl/allyl passivated SiNWs exhibits improved stable electrical output over those based on either methyl or allyl passivated ones. The improved PCE and good stability of the device are ascribed to efficient functionalization of the SiNW surface.

Heterojunction with Organic Thin Layers on Silicon for Record Efficiency Hybrid Solar Cells

“…The device without Liq layer displays the lowest value of 0.801 eV, while the device with 1-nm-thick Liq/Al exhibited a higher value (0.890 eV). Accordingly, the V oc of the device with Al as rear electrode is 0.560 V, which is comparable to the device based on methyl terminated planar Si, [ 22 ] and the V oc of the device with 1 nm Liq/Al as rear electrode reaches 0.609 V. It is worth noting that the value of 0.609 V is comparable with highly engineered Si solar cells with diffused p-n junctions, which typically exhibit V oc of 0.6-0.7 V. [ 23 ] To the best of our knowledge, it is the highest V oc ever reported for hybrid solar cells based on Si and PEDOT:PSS.…”

A Mechanistic Study of the Oxidative Reaction of Hydrogen-Terminated Si(111) Surfaces with Liquid Methanol

“…[1][2] The reactivity of hydrogen-terminated Si(111) (H-Si(111)) surfaces toward organic nucleophiles, including alkenes, [3][4] alkynes, [5][6] amines, [7][8][9][10][11] thiols and disulfides, [12][13] Grignards, [14][15] and alcohols, [16][17][18][19][20][21][22][23][24][25] has been widely exploited to impart desirable functionality to the Si interface. These surface reactions have been used to control the interface between Si and metals, [26][27][28][29][30][31] metal oxides, [32][33][34][35] polymers, [36][37][38][39][40][41] and redox assemblies.…”

Correlation between interface modification and rectifying behavior of p-type Cu2ZnSnS4/n-type Si diodes

“…It is believed that the predominant Si chemical state at the surface is S coordinated Si which has a potential to eliminate surface dangling bonds and strained dimer bonds at the Si (100) surface [29]. Zhang et al [31] suggested that the Si surface termination state plays a key role on the electrical output of the Sibased devices. As compared to a CZTS/as-cleaned n-Si diode, the number of charge traps in Si near the CZTS/Si interfaces is significantly decreased for CZTS/sulfidetreated n-Si diodes.…”