Enhancement of Inverted Polymer Solar Cells Performances Using Cetyltrimethylammonium-Bromide Modified ZnO

Abstract

In this study, the performance and stability of inverted bulk heterojunction (BHJ) polymer solar cells (PSCs) is enhanced by doping zinc oxide (ZnO) with 0–6 wt % cetyltrimethylammonium bromide (CTAB) in the sol-gel ZnO precursor solution. The power conversion efficiency (PCE) of the optimized 3 wt % CTAB-doped ZnO PSCs was increased by 9.07%, compared to a PCE of 7.31% for the pristine ZnO device. The 0–6 wt % CTAB-doped ZnO surface roughness was reduced from 2.6 to 1 nm and the number of surface defects decreased. The X-ray photoelectron spectroscopy binding energies of Zn 2p3/2 (1021.92 eV) and 2p1/2 (1044.99 eV) shifted to 1022.83 and 1045.88 eV, respectively, which is related to strong chemical bonding via bromide ions (Br−) that occupy oxygen vacancies in the ZnO lattice, improving the PCE of PSCs. The concentration of CTAB in ZnO significantly affected the work function of PSC devices; however, excessive CTAB increased the work function of the ZnO layer, resulting from the aggregation of CTAB molecules. In addition, after a 120-hour stability test in the atmosphere with 40% relative humidity, the inverted device based on CTAB-doped ZnO retained 92% of its original PCE and that based on pristine ZnO retained 68% of its original PCE. The obtained results demonstrate that the addition of CTAB into ZnO can dramatically influence the optical, electrical, and morphological properties of ZnO, enhancing the performance and stability of BHJ PSCs.

Surfactant-assisted microwave processing of ZnO particles: a simple way for designing the surface-to-bulk defect ratio and improving photo(electro)catalytic properties

“…61 The bromide anions of CTAB or oxygen ions of Pluronic can ll up the singly ðV þ O Þ or doubly ðV þþ O Þ charged states of oxygen vacancies in the ZnO lattice. 62…”

Nitrogen-Implanted ZnO Nanorod Arrays for Visible Light Photocatalytic Degradation of a Pharmaceutical Drug Acetaminophen

“…Zn 2p 3/2 and Zn 2p 1/2 binding peaks are observed at 1019.41 and 1042.41 eV, respectively. 27,28 This result indicated the existence of a divalent oxidation state in both pristine and N-implanted ZnO samples. For the N−ZnO4 sample, the Zn 2p 3/2 and Zn2p 1/2 peaks showed a slight chemical shift in binding energy compared to pristine ZnO because of N-ion implantation.…”

Interface Modification Enabled by Atomic Layer Deposited Ultra‐Thin Titanium Oxide for High‐Efficiency and Semitransparent Organic Solar Cells

“…[ 62 ] The suppression of −OH and V O concentration with the increase in TiO x ALD cycles could reduce the recombination centers at the ZnO/TiO x interface, thus improving the passivation effect. [ 63 ] To verify the chemical states of the Ti atoms, the binding energy peaks of Ti were fitted from the XPS results, which is shown in Figure . Figure 7a shows that the original ZnO was free of Ti.…”