XPS Analysis of the Improved Operational Stability of Organic Solar Cells Using a V₂O₅ and PEDOT:PSS Composite Layer: Effect of Varied Atmospheric Conditions

Abstract

This work investigates the enhanced stability of organic solar cells (OSCs) fabricated with a hybrid hole-transport layer (HTL) incorporating vanadium pentaoxide (V2O5) nanoparticles in poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) (PEDOT:PSS). OSCs have been fabricated in controlled and ambient atmospheric conditions by employing a pristine PEDOT:PSS HTL and its hybrid variant. Stability and degradation analyses were carried out by using photovoltaic and X-ray photoelectron spectroscopy (XPS) measurements, respectively. Normalized photovoltaic characteristics showed that OSCs with hybrid HTL outperformed the pristine device and retained their performance as compared to their pristine counterparts when the fabrication was carried out in a nitrogen-filled glovebox and devices were tested after encapsulation for 7 days. However, OSCs that were fabricated and characterized in ambient air showed severe degradation in photovoltaic performance, mainly due to a drastic decay in the short circuit current and open circuit voltage for both device variants. Further, XPS was applied to probe the stability of HTL variants under aging in ambient air. The device instability was mainly ascribed to indium diffusion from the anode into the HTL, and its concentration increased from 0.4 to 2.8% within 250 h of ambient exposure of pristine HTL, while an insignificant increase was recorded in the indium content of the hybrid HTL. This confirms the remarkable reduction in indium diffusion brought about by the presence of V2O5 nanoparticles.

Progress in Stability of Organic Solar Cells

“…incorporated vanadium oxide (V 2 O 5 ) into the PEDOT:PSS based hole transport layer and found that the air stability of the device can be profoundly improved. [ 147 ]…”

Mo addition for improved electrochromic properties of V2O5 thick films

“…Another advantageous specificity lies in the facility to improve the electrochromic properties by single or double doping or by addition of other materials and formation of composites [19][20][21][22]. Doping of material in electrochromic host lattice is expected to benefit the coloration efficiency and durability of the host, extending the switching potential range, and enhancing the reaction kinetics [23,24].…”

PEDOT solid‐state polymer supercapacitor assembled with a KI‐doped gel polymer electrolyte

“…The XPS analysis of PEDOT/CP (Figure ) further proves the surface function of the CP and composition of the PEDOT/CP electrode. Apart from the peaks corresponding to the sp2‐hybridized CC (284.8 eV) and the sp3‐hybridized CC (285.1 eV) bonds in the structure of PEDOT, the peaks at 532.9 and 163 eV reveal the existence of S and O element, indicating the successful electrodeposition of the PEDOT on the CP surface …”

“…Apart from the peaks corresponding to the sp2-hybridized C C (284.8 eV) and the sp3-hybridized C C (285.1 eV) bonds in the structure of PEDOT, the peaks at 532.9 and 163 eV reveal the existence of S and O element, indicating the successful electrodeposition of the PEDOT on the CP surface. 39,40 The Thermal Properties of PVA/H 2 SO 4 /KI Electrolyte Figure 4 shows the DSC and TGA curves of PVA/H 2 SO 4 /KI GPE. The peaks observed at 120-150 C are considered as the chain movements caused by water, KI, and other small molecules.…”