On the physics of dispersive electron transport characteristics in SnO₂ nanoparticle-based dye sensitized solar cells

Abstract

The present study elucidates dispersive electron transport mediated by surface states in tin oxide (SnO) nanoparticle-based dye sensitized solar cells (DSSCs). Transmission electron microscopic studies on SnO show a distribution of ∼10 nm particles exhibiting (111) crystal planes with inter-planar spacing of 0.28 nm. The dispersive transport, experienced by photo-generated charge carriers in the bulk of SnO, is observed to be imposed by trapping and de-trapping processes via SnO surface states present close to the band edge. The DSSC exhibits 50% difference in performance observed between the forward (4%) and reverse (6%) scans due to the dispersive transport characteristics of the charge carriers in the bulk of the SnO. The photo-generated charge carriers are captured and released by the SnO surface states that are close to the conduction band-edge resulting in a very significant variation; this is confirmed by the hysteresis observed in the forward and reverse scan current-voltage measurements under AM1.5 illumination. The hysteresis behavior assures that the charge carriers are accumulated in the bulk of electron acceptor due to the trapping, and released by de-trapping mediated by surface states observed during the forward and reverse scan measurements.

Fabrication of Dye‐Sensitized Solar Cells Based on Novel Mixed Tungsten–Molybdenum and Tungsten–Titanium Oxides Nanoparticles Prepared by Impulse Underwater Plasma

“…In general, one of the disadvantages of DSSCs based on TiO 2 nanoparticles is their high surface recombination rate due to the presence of surface defects and traps. [ 46 ] The DSSC made from sample 2 showed a higher open‐circuit voltage, indicating better cell performance in terms of electron transport and FF improvement. Pure tungsten oxide has suitable electron transport properties, but the electron lifetime and recombination are degraded due to the presence of surface defects.…”

Investigation of low-cost magnesium stannate transparent conductive oxide layer: optical, structural and electrical properties and photovoltaic applications

“…The MHz region represented by small semicircle in the spectra and this lower frequency region allocated to the Nernst diffusion of I3-within the electrolyte. Usually in the centre frequency region presided by huge semicircle and the range for this region is usually in between the range of (10-100 Hz) is ascribed to that of charge transfer resistance at both the interfaces of Titanium dioxide/dye/electrolyte (Rct2) and the semicircle in the higher frequency region (kHz) is allocated at the counter electrode/ electrolyte interface (Rct1) to the charge transfer resistance [43][44][45].…”

The Influence of Carboxyl-Functionalized Carbon Dots on Ethanol Selectivity in Gas Sensing

“…In particular, when SnO 2 is used as the sensing material, gas sensors can exhibit advantages such as low resistance, high sensitivity, and fast response-recovery speeds. They are commonly employed for monitoring certain combustible, toxic, and pollutant gases [4,5].…”