A Thin In₂S₃ Interfacial Layer for Reducing Defects and Roughness of Cu₂ZnSn(S,Se)₄ Thin‐Film Solar Cells

Abstract

Cu 2 ZnSn(S,Se) 4 (CZTSSe) has generated considerable research interest owing to its composition of abundant elements and excellent light-absorption properties. However, CZTSSe thin-film solar cells suffer from a considerable deficit in the open-circuit voltage (V OC ), which is mainly due to the severe interfacial recombination induced by the rough surface of CZTSSe and numerous physical defects. In this study, to improve the morphology and reduce the interfacial recombination, an In 2 S 3 passivation layer was introduced between the CZTSSe and CdS layers via a chemical bath deposition process, and the effects of the In 2 S 3 layer on the device performance were systematically examined by performing various electrodynamic analyses. The CZTSSe solar cells with thin In 2 S 3 layers exhibited impressive increases in V OC and conversion efficiency (from 7.33 to 9.24 %), due to the suppression of physical defects and the refined surface morphology resulting from filling the voids and pinholes. In addition, the nanoscale roughness of the In 2 S 3 /CZTSSe surface increased the number of nucleation sites for the CdS nuclei, which may reduce the activation energy of the heterogeneous nucleation. The presence of In 2 S 3 layer resulted in uniform growth of CdS without macroscopic CdS agglomerates (i. e., reduced roughness of full devices), which improved the quality of the interface. These findings confirmed that the reduction of physical defects and the improved deposition of the CdS layer enabled by the added In 2 S 3 passivation layer improved the device performance.

Atomic Layer Deposition-Free Monolithic Perovskite/Perovskite/Silicon Triple-Junction Solar Cells

“…Transient photovoltage decay (TPVD) analysis reveals that the device with 15% urea showed a longer minority carrier lifetime (Figure E), indicating a reduced nonradiative recombination due to the defect passivation . The temperature dependency of V oc (Figure F) also shows that the difference between the activation energy of the dominant recombination process ( E A ) and E g in the device with the urea additive (0.06 eV) is smaller than that without the urea additive (0.27 eV), indicating the excellent defect passivation capability of the urea additive. , …”

“…35 The temperature dependency of V oc (Figure 2F) also shows that the difference between the activation energy of the dominant recombination process (E A ) and E g in the device with the urea additive (0.06 eV) is smaller than that without the urea additive (0.27 eV), indicating the excellent defect passivation capability of the urea additive. 36,37 Before the fabrication of 3J devices, 2J tandem devices were fabricated by directly preparing a 1.96 eV PSC on a transparent 1.56 eV PSC without any ALD layer, for which the optimal composition of the ACN/MA volatile solvent was used (Figure S11). The 2J device exhibits a PCE of 15.35% with J sc , V oc , and FF of 10.79 mA/cm 2 , 2.1 V, and 67.7%, respectively (Figure 3A), indicating no degradation of the underneath subcell.…”

Enhancing the efficiency of Cu2ZnSn(S,Se)4solar cells by variable-temperature sulfoselenization

“…Moreover, a dense CSTSSe surface can combine with the CdS buffer layer to form a PN junction with good properties. 35 As a result, both the open-circuit voltage ( V oc ) and short-circuit current density ( J sc ) would be improved. 36…”

CZTSSe solar cells: insights into interface engineering

“…, TiO 2 , 110 SnO 2 , 111 Al 2 O 3 , 98–100 and In 2 S 3 (ref. 112)) have been developed as passivation layers for CZTSSe. 33 The primary role of most passivation layers is to passivate the interface defects and optimize the band alignment and thus reduce the interface recombination.…”

“…Recently, an In 2 S 3 passivation layer was used with the CZTSSe/CdS interface to improve the front interface roughness and reduce interfacial recombination, and it was demonstrated that this method could effectively control the surface morphology and defect density of CZTSSe thin-film solar cells. 112 The presence of the In 2 S 3 layer led to an homogeneous growth of CdS without macroscopic CdS agglomeration ( i.e. , a reduced roughness of the full device), thereby improving the quality of the heterojunction (as shown in Fig.…”