ZnS Ultrathin Interfacial Layers for Optimizing Carrier Management in Sb₂S₃-based Photovoltaics

Abstract

Antimony chalcogenides represent a family of materials of low toxicity and relative abundance, with a high potential for future sustainable solar energy conversion technology. However, solar cells based on antimony chalcogenides present open-circuit voltage losses that limit their efficiencies. These losses are attributed to several recombination mechanisms, with interfacial recombination being considered as one of the dominant processes. In this work, we exploit atomic layer deposition (ALD) to grow a series of ultrathin ZnS interfacial layers at the TiO 2 /Sb 2 S 3 interface to mitigate interfacial recombination and to increase the carrier lifetime. ALD allows for very accurate control over the ZnS interlayer thickness on the ångström scale (0–1.5 nm) and to deposit highly pure Sb 2 S 3 . Our systematic study of the photovoltaic and optoelectronic properties of these devices by impedance spectroscopy and transient absorption concludes that the optimum ZnS interlayer thickness of 1.0 nm achieves the best balance between the beneficial effect of an increased recombination resistance at the interface and the deleterious barrier behavior of the wide-bandgap semiconductor ZnS. This optimization allows us to reach an overall power conversion efficiency of 5.09% in planar configuration.

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

“…[3,6,20] In terms of ETL, two types of compounds are widely employed, namely, binary oxides, such as TiO 2 , SnO 2 , and sulfides, such as CdS, ZnS. [21][22][23][24][25] The point to emphasize here is that the ETL serves a dual role to Sb 2 (S,Se) 3 device: it not only promotes the separation of charge carriers by forming a heterojunction with the light absorber layer, but also acts as the growth matrix that directly influences the characteristics of Sb 2 (S,Se) 3 film. In the case of oxide ETL, a weak orientating effect on Sb 2 (S,Se) 3 is usually observed because of the large lattice mismatch between them.…”

Elucidating Mechanistic Details of Photo-Induced Charge Transfer in Antimony Sulfide-Based p-i-n Junctions

“…We posit that this τ 2 lifetime is the key in rationalizing the functional operation of PV constructed with these materials. We have recently shown that the efficiency of the completed solar cells fabricated with these materials follows the same trend as the τ 2 lifetime . That is, the efficiency of the cells increases from 0 to 10 cycles of ZnS and then falls off dramatically at 15 cycles.…”

“…This series of measurements is instrumental in verifying the photophysical (Figure ) picture we have proposed for this system and is critical to understanding the functional operation of PV cells fabricated with these materials …”

“…We have recently shown that the efficiency of the completed solar cells fabricated with these materials follows the same trend as the τ 2 lifetime. 23 That is, the efficiency of the cells increases from 0 to 10 cycles of ZnS and then falls off dramatically at 15 cycles. These trends taken together suggest that (1) the τ 2 lifetime corresponds to reverse transfer and (2) by blocking reverse electron transfer (as long as forward electron transfer is facile in the thinner ZnS samples), charge remains separated longer and is more likely to be extracted into an external circuit.…”

Efficient All‐Inorganic Sb2S3 Solar Cells with Matched Energy Levels Using Sb2Se3 as Hole Transport Layers

“…Inorganic hole materials show large potential for low-cost and highly efficient Sb 2 S 3 solar cells. [16][17][18][19] Jin et al used NiO x as HTL and obtained PCE of 3.51% for Sb 2 S 3 solar cells. [18] Chen and co-workers reported the material V 2 O 5 HTL for efficient Sb 2 S 3 planar solar cells.…”