Formation and characterization of one-dimensional ZnS nanowires for ZnS/P3HT hybrid polymer solar cells with improved efficiency

Publication date: 1 September 2018
Source:Applied Surface Science, Volume 451
Author(s): Katarzyna Matras-Postołek, Adam Żaba, Elżbieta M. Nowak, Paweł Dąbczyński, Jakub Rysz, Jerzy Sanetra
Photovoltaic performance of hybrid devices consisting of zinc sulphide (ZnS) one-dimensional (1D) nanowires and P3HT polymer was studied. As we previously reported, hybrid solar cell architecture based on ZnS, where open circuit voltage reaches high value, deserves special attention. In this work, compared to our previous research, zero-dimensional (0D) ZnS nanoparticles were replaced by one-dimensional (1D) ZnS nanowires synthesized simply with a hot injection method. In order to improve the charge transport in hybrid solar cells, additionally, the initial ligand of octadecylamine (ODA) was partially replaced by the o-phenylenediamine. The as-synthesized products were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy, photoluminescence (PL) spectroscopy, energy dispersive spectroscopy (EDS), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The performance of the devices significantly depended on the concentration of one-dimensional ZnS nanowires incorporated in the active layer (optimal 10 wt.%) and their morphology. In the presented work, we showed that devices based on 1D ZnS nanowires were distinguished by the high value of Voc parameter (with the maximum achieved value of 0.634 V). Also we investigated the spatial layout of nanocrystals in the device, depending on its post treatment, using atomic force microscopy (AFM), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and ultraviolet photoelectron spectroscopy (UPS). Our study showed spatial segregation of nanocrystals to both interfaces with electrodes, and also we showed significant changes (0.71 eV at the top) in the PEDOT:PSS work function after mixing with ZnS nanocrystals, which resulted in an increase in the difference in contact potential at respective electrodes, which explained the high value of Voc. In comparison to our previous study, by replacing an active layer of the 0D ZnS nanocrystals with 1D ZnS nanowires, nearly a triple increase of the overall efficiency (maximum of % η of 0.568) of the device was observed.

Graphical abstract

https://ift.tt/2jyNTdo