Key Factors Affecting the Performance of Sb2S3-sensitized Solar Cells During an Sb2S3 Deposition via SbCl3-thiourea Complex Solution-processing

Summary

This work provides a detailed experimental procedure for the deposition of Sb₂S₃ on a mesoporous TiO₂ layer using a SbCl₃-thiourea complex solution for applications in Sb₂S₃-sensitized solar cells. This article also determines key factors governing the deposition process.

Abstract

Sb₂S₃ is considered as one of the emerging light absorbers that can be applied to next-generation solar cells because of its unique optical and electrical properties. Recently, we demonstrated its potential as next-generation solar cells by achieving a high photovoltaic efficiency of > 6% in Sb₂S₃-sensitized solar cells using a simple thiourea (TU)-based complex solution method. Here, we describe the key experimental procedures for the deposition of Sb₂S₃ on a mesoporous TiO₂ (mp-TiO₂) layer using a SbCl₃-TU complex solution in the fabrication of solar cells. First, the SbCl₃-TU solution is synthesized by dissolving SbCl₃ and TU in N,N-dimethylformamide at different molar ratios of SbCl₃:TU. Then, the solution is deposited on as-prepared substrates consisting of mp-TiO₂/TiO₂-blocking layer/F-doped SnO₂ glass by spin coating. Finally, to form crystalline Sb₂S₃, the samples are annealed in an N₂-filled glove box at 300 °C. The effects of the experimental parameters on the photovoltaic device performance are also discussed.

Introduction

Antimony-based chalcogenides (Sb-Chs), including Sb₂S₃, Sb₂Se₃, Sb₂(S,Se)₃, and CuSbS₂, are considered to be emerging materials that can be used in next-generation solar cells^{1,2,3,4,5,6,7,8}. However, photovoltaic devices based on Sb-Chs light absorbers have not yet reached the 10% power conversion efficiency (PCE) required to d....

Protocol

1. Synthesis of the TiO₂-BL Solution

1. Prepare 2 transparent vials with a 50 mL volume.
2. Add 20 mL of ethanol to 1 vial (V1) and seal V1.
3. Transfer V1 to an N₂-filled glove box with a moisture-controlled system of an H₂O level of < 1 ppm.
4. Add 1.225 mL of titanium (IV) isopropoxide (TTIP) to V1 using a syringe with a 0.45 µm PVDF filter and gently stir the mixture for at least 30 min.
   NOTE: This step must be performed in a glove box (or under very low humidity conditions) since TTIP is highly sensitive to moisture. If the TTIP solution is not transparent or white precipitates are obs....

Results

Figure 1 shows a schematic representation of the experimental procedure for the Sb₂S₃ deposition on the substrate of mp-TiO₂/TiO₂-BL/FTO glass. Figure 1d shows the basic properties and scheme of a typical product fabricated by the method described herein. The main X-ray diffraction (XRD) pattern is well matched with that of a stibnite Sb₂S₃ structure

Discussion

TiO₂-BL is widely used as a hole-blocking layer in solar cells. As shown in Figure 2, a large difference was observed in the device performance depending on the TiO₂-BL thickness. Therefore, its thickness should be optimized to obtain the best overall device performance, because it critically acts as a hole-blocking layer to prevent any direct contact between FTO and hole-transporting materials¹¹. It should be noted that the optimum thickness var.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Ethyl alcohol, Pure, >99.5%	Sigma-Aldrich	459836
Titanium(IV) isopropoxide 97%	Aldrich	205273
Nitic acid, ACS reagent, 70%	Sigma-Aldrich	438073
Antimony(III) chloride	Sigma-Aldrich	311375
Thiourea	Sigma-Aldrich	T7875
N,N-Dimethylformamide, anhydrous, 99.8%	Sigma-Aldrich	227056
TiO2 paste with 50 nm particles	ShareChem	SC-HT040
Poly(3-hexylthiophene)	1-Material	PH0148
Chlorobenzene	Sigma-Aldrich	284513
FTO/glass (8 Ohmos/sq)	Pilkington
Spin coater	DONG AH TRADE CORP	ACE-200
Hot plate	AS ONE Corporation	HHP-411
Glove box	KIYON	KK-021AS
UV OZONE Cleaner	AHTECH LTS	AC-6
Furnace	WiseTherm	FP-14
UV/Vis Absorption spectroscopy	PerkinElmer	Lambda 750
Multifunctional evaporator with glove box	DAEDONG HIGH TECHNOLOGIES	DDHT-SDP007