Efficient Antimony‐Based Solar Cells by Enhanced Charge Transfer

Abstract

The main mechanism of most solar cells is that the light produces photogenerated electrons and holes, which are transferred to the electron transport layer and the hole transport layer (HTL), respectively. Then, these holes and electrons are transported to the anode and cathode, respectively, to generate electric current. Thus, charge transfer is a crucial process to fabricate efficient solar cells. Here, a fast vapor process is developed to fabricate SbSI and SbSI‐interlayered Sb2S3 solar cells by annealing an Sb2S3 film and SbI3 powder in an inert gas atmosphere. The charge transfer of the vapor‐processed SbSI solar cells is increased by shortening the path length from SbSI to the HTL. This is achieved by an intimate contact between SbSI and the HTL, which is obtained by optimizing the morphology of SbSI, resulting in a record power conversion efficiency (PCE) of 3.62% in pure SbSI‐based solar cells under standard illumination at 100 mW cm−2. In addition, the charge transfer of the SbSI‐interlayered Sb2S3 solar cells is enhanced by increasing the external driving force, an energetically favorable driving force provided by the TiO2/Sb2S3/SbSI/HTM structure, and the best‐performing SbSI‐interlayered Sb2S3 solar cell exhibits a PCE of 6.08%.

Wide Bandgap Sb2S3 Solar Cells

“…The addition of PCPDTBT positively changed the device properties and improved the PCE 19.61% compared to the control device. In 2019, Seok et al [54] improved the device performance by ferroelectric antimony sulfoiodide (SbSI) interlayer among absorber and HTL. The interlayer effectively extracted the holes from Sb 2 S 3 and made the route shorten for holes from Sb 2 S 3 to PCPDTBT, and the efficiency was improved from 4.78% to 5.38%.…”

Recent Progress in Fabrication of Antimony/Bismuth Chalcohalides for Lead-Free Solar Cell Applications

“…Therefore, developing methods to control and optimize the properties of chalcohalides suitable for solar cells is imperative. Sb/Bi chalcohalides used for solar cells are prepared by many techniques including spray pyrolysis [ 40 ], spin coating [ 24 , 45 , 46 , 47 , 51 ], solvothermal synthesis [ 49 , 53 ], and mixed techniques [ 23 , 38 , 48 , 65 ]. In this section, the fabrication methods reported to date are categorized and described, with the solar cells fabricated presented by the method in Table 4 .…”

“…In addition, the resulting films were not completely homogeneous. To overcome these limitations, they introduced an SbI 3 vapor process instead of the SbI 3 solution process in step 2 ( Figure 4 c), enabling the production of SbSI with improved homogeneity without repeating step 2 [ 65 ] and yielding a better PCE of 3.62% for SbSI solar cells. The study by the Seok group clearly demonstrated a two-step method for fabricating different chalcohalides.…”

“…Other chalcohalides can also serve as interlayers. According to the Seok group, the SbSI interlayer formed on the Sb 2 S 3 surface provides an energetically favorable driving force for photogenerated carriers [ 65 ]. Thus, the SbSI-interlayered Sb 2 S 3 device showed better performance than the Sb 2 S 3 device, with the best PCE of 6.08%.…”

“…Adapted from [ 23 ], with permission from John Wiley and Sons, 2019; ( c ) Schematic illustration of the two processes utilized in step 2 of the SbSI fabrication. Adapted from [ 65 ], with permission from John Wiley and Sons, 2019.…”