Solution-Processed Sb₂S₃ Planar Thin Film Solar Cells with a Conversion Efficiency of 6.9% at an Open Circuit Voltage of 0.7 V Achieved via Surface Passivation by a SbCl₃ Interface Layer

Interfaces in Sb2S3 thin-film solar cells strongly affect their open-circuit voltage (VOC) and power conversion efficiency (PCE). Finding an effective method of reducing the defects is a promising approach for increasing the VOC and PCE. Herein, the use of an inorganic salt SbCl3 is reported for post-treatment on Sb2S3 films for surface passivation. It is found that a thin SbCl3 layer could form on the Sb2S3 surface and produce higher efficiency cells by reducing the defects and suppressing nonradiative recombination. Through density functional theory calculations, it is found that the passivation of the Sb2S3 surface by SbCl3 occurs via the interactions of Sb and Cl in SbCl3 molecules with S and Sb in Sb2S3, respectively. As a result, incorporating the SbCl3 layer highly improves the VOC from 0.58 to 0.72 V; an average PCE of 6.9 ± 0.1% and a highest PCE of 7.1% are obtained with an area of 0.1 cm2. The achieved PCE is the highest value in the Sb2S3 planar solar cells. In addition, the incorporated SbCl3 layer also leads to good stability of Sb2S3 devices, by which 90% of the initial performance is maintained for 1080 h of storage under ambient humidity (85 ± 5% relative humidity) at room temperature

Transparent MoS₂/PEDOT Composite Counter Electrodes for Bifacial Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) are solar energy conversion devices with high efficiency and simple fabrication procedures. Developing transparent counter electrode (CE) materials for bifacial DSSCs can address the needs of window-type building-integrated photovoltaics (BIPVs). Herein, transparent organic–inorganic hybrid composite films of molybdenum disulfide and poly­(3,4-ethylenedioxythiophene) (MoS2/PEDOT) are prepared to take full advantage of the conductivity and electrocatalytic ability of the two components. MoS2 is synthesized by hydrothermal method and spin-coated to form the MoS2 layer, and then PEDOT films are electrochemically polymerized on top of the MoS2 film to form the composite CEs. The DSSC with the optimized MoS2/PEDOT composite CE shows power conversion efficiency (PCE) of 7% under front illumination and 4.82% under back illumination. Compared with the DSSC made by the PEDOT CE and the Pt CE, the DSSC fabricated by the MoS2/PEDOT composite CE improves the PCE by 10.6% and 6.4% for front illumination, respectively. It proves that the transparent MoS2/PEDOT CE owes superior conductivity and catalytic properties, and it is an excellent candidate for bifacial DSSC in the application of BIPVs