Controlled growth of SbSI thin films from amorphous Sb2S3 for low-temperature solution processed chalcohalide solar cells

Abstract

We report a simple solution processing method for fabricating low-temperature SbSI solar cells. The method consists of two steps: the formation of amorphous Sb2S3 and its transformation to SbSI. A pure SbSI phase with a high crystallinity was obtained at a low temperature of 200 °C. In addition, the SbSI morphology was controlled by tuning the input ratio of SbCl3:thiourea and a dense film was obtained at a ratio of 1:1.3. A planar SbSI solar cell thus-fabricated exhibits a short-circuit current density of 5.45 mA cm−2, an open-circuit voltage of 0.548 V, and a fill factor of 0.31, corresponding to a power conversion efficiency of 0.93% under a 100 mW cm−2 illumination condition.

Controlled Growth of BiSI Nanorod-Based Films through a Two-Step Solution Process for Solar Cell Applications

“…The different BiSI formation by the Bi:S molar ratio may be explained in terms of the contribution of excess TU to BiSI formation. The TU as a sulfur source should be sufficiently supplied at each step to compensate for the loss of volatile TU at our annealing temperature of 200 • C. In addition, an excess TU may contribute to stabilizing the Bi-TU complex in the solution [11,20], enabling a stable supply of S. Thus, the BiSI formation is more enhanced as the more TU is supplied as shown in Figure 2. However, at a highly excess TU condition, organic residues derived from residual TU may interfere with BiSI formation.…”

“…As a result, the BiSI with maximum intensity can be obtained at the specific ratio of Bi:S = 1:3. Interestingly, the optimum ratio of Bi:S (1:3) is same as that of Sb:S used for SbSI [11], although the solution method and the material are quite different. Besides, the TU plays a similar role in forming the crystalline phase in both materials.…”

“…Therefore, it is still necessary to develop an approach that can control the key variables, such as the crystal structure, morphology, and optoelectronic properties. We recently developed a simple solution method for typical Sb chalcohalides, SbSI, via a two-step process [11]: (i) formation of Sb 2 S 3 and (ii) its conversion to SbSI based on the simple chemical reaction of Sb 2 S 3 + SbI 3 → 3SbSI. With this method, the structure and morphology of SbSI were successfully controlled by tuning experimental parameters at each step.…”

“…(a) UPS spectra of the cut-off and valence band edge region for the BiSI nanorods film, and (b) the derived energy-level band diagram. For comparison, a conducting oxide (FTO), ETL (TiO 2 ), HTM (P3HT), and electrode (Au) were drawn based on a previous study[11].…”

A Ferroelectric-Photovoltaic Effect in SbSI Nanowires

“…A thin film of SbSI has been prepared by solution processing, followed by thermal annealing leading to a reaction between antimony trisulfide (Sb 2 S 3 ) and antimony triiodide (SbI 3 ). A similar approach for preparation of a solar cell based on a thin film of SbSI has been proposed by Choi et al [36]. It consists of two steps—the formation of amorphous Sb 2 S 3 and its transformation to SbSI.…”