Precursor solution chemistry via water additive enabling CZTSSe solar cells with over 12% efficiency

Abstract

High-quality absorber films are imperative for highly efficient Cu 2 ZnSn(S,Se) 4 (CZTSSe) thin-film solar cells. Precursor solution chemistry, interconnected with thin-film nucleation and the crystal growth process, should be studied insightfully. Thus, creative rationales and strategies could be proposed to improve the absorber quality, carrier characteristics, and hence device performance. However, the research on precursor solution chemistry in CZTSSe solar cells is still in its infancy. In this study, a facile eco-friendly additive strategy is reported to tailor the 2-methoxyethanol-based CZTS precursor solution chemistry. Incorporating water additives improves the homogeneity and thermogravimetric characteristics of a precursor solution by adjusting the particle sizes and coordination behavior inside the precursor solution. After the tailoring of the precursor solution chemistry, CZTSSe absorbers with high quality are fabricated. Hence, benefiting from the carrier dynamics enhancement, a CZTSSe device with a certified power conversion efficiency of 12.07% is achieved. The results open an avenue in precursor solution chemistry regulation through the use of eco-friendly additives to design highly efficient kesterite CZTSSe solar cells.

Delafossite CuAlO2 Modification‐Induced Synergistic Passivation Effects for Heterojunction Interface and Absorber toward Efficient Kesterite Solar Cells

“…Therefore, electric parameters including R S , G Sh , R Sh , A, and J 0 of solar cells are calculated to perform a comprehensive and deep understanding concerning the improvement mechanism of V OC and FF for C-110 and C-150, as summarized in Table 4. [57] By analyzing the data in Table 3 and Table 4, the increased V OC in C-110 and C-150 is mainly benefited from the higher R Sh and lower J 0 . To be specific, the higher R Sh is mainly attributed to the enhanced absorber crystalline quality revealed in Figure 2a-c and also observed from the cross-sectional SEM images of the whole device, as shown in Figure 3f-h.…”

“…Therefore, electric parameters including R S , G Sh , R Sh , A, and J 0 of solar cells are calculated to perform a comprehensive and deep understanding concerning the improvement mechanism of V OC and FF for C‐110 and C‐150, as summarized in Table 4 . [ 57 ]…”

A critical review of solution-process engineering for kesterite thin-film solar cells: current strategies and prospects

“…CZTSSe absorber layers with additives exhibited improved crystalline quality and enhanced carrier dynamics in the devices, and achieved a device efficiency of 12.07%. 108 The band tailing and non-radiative recombination losses caused by deep-level defect states and defect clusters in the bulk of CZTSSe can be alleviated through cation doping. X. Zhao et al investigated the impact mechanism of Ga cation doping on CZTSSe material by comparing the effects of physical and chemical doping methods.…”

Progress and prospectives of solution-processed kesterite absorbers for photovoltaic applications

“…34 In addition, Zhao et al reported a simple and environmentally friendly additive strategy by adding water additives, which can improve the homogeneity and thermogravimetric characteristics of the precursor solution by adjusting the particle size and coordination behavior of the precursor solution, achieving a certified CZTSSe device with a PCE of 12.07%. 140 In 2022, an efficiency of 12.87% was achieved using a two-step cooling strategy, which can suppress the Cu Zn and Sn Zn defects and defect clusters synergistically. 141 Unlike amine-thiol, DMSO and other solvents, the fabrication of CZTSSe solars by EGME solvent is not only insensitive to oxygen and water in the air but also does not show decomposition or uneven morphology.…”