Planar Heterojunction Solar Cell Employing a Single-Source Precursor Solution-Processed Sb₂S₃ Thin Film as the Light Absorber

Abstract

We discuss here a solution-processed thin film of antimony trisulphide (Sb 2 S 3 ; band gap ≈ 1.7 eV; electronic configuration: ns 2 np 0 ) for applications in planar heterojunction (PHJ) solar cells. An alternative solution processing method involving a single-metal organic precursor, viz., metal–butyldithiocarbamic acid complex, is used to grow the thin films of Sb 2 S 3 . Because of excess sulphide in the metal complex, the formation of any oxide is nearly retarded. Sb 2 S 3 additionally displays structural anisotropy with a ribbon-like structure along the [001] direction. These ribbon-like structures, if optimally oriented with respect to the electron transport layer (ETL)/glass substrate, can be beneficial for light-harvesting and charge-transport properties. A PHJ solar cell is fabricated comprising Sb 2 S 3 as the light absorber and CdS as an ETL coated on to FTO. With varying film sintering temperature and thickness, the typical ribbon-like structures predominantly with planes hkl : l = 0 stacked horizontally along with respect to CdS/FTO are obtained. The morphology of the films is observed to be a function of the sintering temperature, with higher sintering temperatures yielding compact and smooth films with large-sized grains. Maximum photon to electricity efficiency of 2.38 is obtained for PHJ solar cells comprising 480 nm thick films of Sb 2 S 3 sintered at 350 °C having a grain size of few micrometers (>5 μm). The study convincingly shows that improper grain orientation, which may lead to nonoptimal alignments of the intrinsic structure with regard to the ETL/glass substrate, is not the sole parameter for determining photovoltaics performance. Other solution-processing parameters can still be suitably chosen to generate films with optimum morphology, leading to high photon to electricity efficiency.

Tailoring the Crystallographic Orientation of a Sb2S3 Thin Film for Efficient Photoelectrochemical Water Reduction

“…15,16 In contrast, the carrier transport along the direction is much more efficient because it is governed by intraribbon carrier transport with a reduced recombination probability. 18 Indeed, Roy et al, by studying the electric and magnetic properties of a single Sb 2 S 3 crystal, confirmed that the conductivity along the [hk1] direction was almost 2 orders of magnitude higher than that along the [hk0] direction. 19 In addition, the surfaces orthogonal to the [hk1] orientation usually have the lowest surface energies and no dangling bonds, thereby reducing the surface trap sites in the Sb 2 S 3 film.…”

“…Due to its unique quasi-1D crystal structure, the optoelectronic properties of Sb 2 S 3 strongly depend on its crystallographic orientation. , The orthorhombic Sb 2 S 3 has a two-dimensional layered structure composed of infinite (Sb 4 S 6 ) n chains (ribbons) along the c axis through S–Sb covalent bonds, which are linked by weak van der Waals (vdWs) interaction along the b axis. − This quasi-1D crystal structure of Sb 2 S 3 is responsible for its direction-dependent carrier transport property. The carrier transport along the [ hk 0] direction is inefficient because the carrier transport mechanism along this direction is interchain or interlayer hopping. , In contrast, the carrier transport along the [ hk 1] direction is much more efficient because it is governed by intraribbon carrier transport with a reduced recombination probability . Indeed, Roy et al, by studying the electric and magnetic properties of a single Sb 2 S 3 crystal, confirmed that the conductivity along the [ hk 1] direction was almost 2 orders of magnitude higher than that along the [ hk 0] direction .…”

Controllable Solution‐Phase Epitaxial Growth of Q1D Sb2(S,Se)3/CdS Heterojunction Solar Cell with 9.2% Efficiency

“…[4][5][6] The nontoxicity and earth-abundance of its constituents make Sb 2 (S,Se) 3 a promising candidate to compete with existing materials for commercial photovoltaics. [7] Moreover, Sb 2 (S,Se) 3 has a stable single orthorhombic phase with a Q1D crystal structure (Figure S1, Supporting Information), [8,9] resulting in anisotropic electrical properties in the film. [10] It has been reported that conductivity along the (Sb 4 X 6 ) n (X = S or Se) ribbons (c-axis) is much higher than the other directions that require electron hopping between adjacent ribbons.…”

Numerical Simulation of Non-toxic ZnSe Buffer Layer to Enhance Sb2S3 Solar Cell Efficiency Using SCAPS-1D Software

“…But from 10 3 Ω to 10 7 Ω there is no change in 𝐽 𝑆𝐶 . The Fill Factor has been increased from 25.0271% to 73.2517% with the increase in shunt resistance [27]- [30]. The conversion efficiency has increased from 10Ω to 10 6 Ω, but after 10 6 Ω, efficiency tends to be constantly shown in Fig.…”