n-Type Doping of Sb₂S₃ Light-Harvesting Films Enabling High-Efficiency Planar Heterojunction Solar Cells

Abstract

SbS is a kind of new light-absorbing material possessing high stability in ambient environment, high absorption coefficient in the visible range, and abundant elemental storage. To improve the power conversion efficiency of SbS-based solar cells, here we control the defect in SbS absorber films. It is found that the increase of sulfur vacancy is able to upgrade photovoltaic properties. With the increase in sulfur vacancy, the carrier concentrations are increased. This n-type doping gives rise to an upshift of the Fermi level of SbS so that the charge transport from SbS to the electron selection material becomes dynamically favorable. The introduction of ZnCl in film fabrication is also found to regulate the film growth for enhanced crystallinity. Finally, the photovoltaic parameters, short-circuit current density, open-circuit voltage, and the fill factor of the device based on the SbS film are all considerably enhanced, boosting the final power conversion efficiency from 5.15 to 6.35%. This efficiency is the highest value in planar heterojunction SbS solar cells and among the top values in all kinds of SbS solar cells. This research provides a fundamental understanding regarding the properties of SbS and a convenient approach for enhancing the performance of SbS solar cells.

Enhanced Electrical Conductivity of Sb2S3 Thin Film via C60 Modification and Improvement in Solar Cell Efficiency

“…Very recently, Tang et al reported controllable sulfur vacancy defect by introducing Zn ion into the films. The behavior of electron concentration in Sb 2 S 3 layer was observed to increase with sulfur vacancy defects, which resulted in reduced series resistance and increased recombination resistance for the Sb 2 S 3 thin film solar cells …”

Review of Recent Progress in Antimony Chalcogenide‐Based Solar Cells: Materials and Devices

“…Considering the slow growth rate and strict growth requirements of ultrahigh vacuum for the ALD process, it is desirable to develop a simple industrial‐scale approach to reduce the cost and time of the process and produce high‐quality Sb 2 S 3 films with higher PCE performance. Recently, the efficiency of Sb 2 S 3 solar cells was improved to 6.35% through n‐type doping of Sb/Tu solution processed Sb 2 S 3 , which is currently the highest value for planar Sb 2 S 3 solar cells . Previous research has indicated that Sb 2 S 3 shows low conductivity and mobility, which is mainly caused by low carrier concentrations, surface defects and bulk defects in Sb 2 S 3 films.…”

“…d) Corresponding photocurrent density–voltage responses of devices with different doping concentrations. Reproduced with permission . Copyright 2018, American Chemical Society.…”

Alcohol Vapor Post‐Annealing for Highly Efficient Sb2S3 Planar Heterojunction Solar Cells

“…Compared with the mesoporous structure, planar heterojunction could avoid high‐temperature annealing and reduce interface defects . Various methods have been proposed to prepare Sb 2 S 3 films in planar heterojunction solar cells, including spray pyrolysis, chemical bath deposition, thermal evaporation, atomic layer deposition, and fast chemical approach (FCA), and so on. Among these methods, FCA is an attractive route due to its simple process and fast crystal growth .…”

“…However, the grain‐size of Sb 2 S 3 films obtained from the FCA process is relatively small. It has been reported that doping with alkali metals or ZnCl 2 can improve the grain‐size and crystallinity of Sb 2 S 3 films, and the PCE of Sb 2 S 3 solar cells was boosted . Therefore, it is important to control the morphology and crystallinity of the solution‐processed films to achieve higher efficiency.…”