Modulation Effect of the Zn/Sn Ratio on Performance of Chloride-Fabricated CZTSSe Cells for Boosting 10%-Beyond Efficiencies

Abstract

The cation ratio in Cu-poor and Zn-rich CZTSSe absorbers is key to decide the photovoltaic performance of CZTSSe solar cells, while its toleration and the influence mechanism is still not clear. In this work, for single-layer-structured CZTSSe absorbers spin-coated from metal chloride precursors with constant Cu and Zn values, the Zn/Sn ratio is regulated in the range of 0.8∼1.6. It is found that the Zn/Sn ratio has great influence on the morphology and electrical properties of the CZTSSe absorbers and thus the performance parameters of the CZTSSe cells. Comparatively, the results show that a 1.2 Zn/Sn ratio can boost the photovoltaic efficiency to 10.65% with a relatively high open-circuit voltage (V OC) of 481 mV and a reduced V OC-deficit of 585 mV. Detailed studies indicate that the 1.2 Zn/Sn ratio could favor the large-grain growth, increase the carrier concentration, suppress the carrier recombination, and reduce the band-tail effects and Urbach energy, thus leading to the highest efficiency with superior photovoltaic performance. The optimization of the Zn/Sn ratio in chloride precursor-coated CZTSSe absorbers would be beneficial for in-depth understanding of the effect mechanism of the element ratio on device performance.

Improvement of Performance of Cu2ZnSn(S, Se)4 Solar Cells by Low‐Temperature Annealing of B‐Doped CdS

“…J L is related to depletion region width ( W d ), I CdS , and the bandgap ( E g ) of the absorber. From literatures about CZTSSe and CIGS solar cells published previously, [ 29–34 ] we found FF and V oc and PCE increase with increasing W d , as shown in Figure S1, Supporting Information (in Section S1, Supporting Information). So, widening W d is also an effective route to enhance V oc and FF.…”

Multifunctional black phosphorus pressure sensors with bending angle monitoring and direction recognition characteristics

“…The Cu 2 ZnSn(S,Se) 4 solar cell has a number of advantages including nontoxic elements, long-term stability, lightweight, and high flexibility. 47,48 The photograph and fundamental properties of the Cu 2 ZnSn(S,Se) 4 solar cell are shown in Fig. S15 and S16 (ESI †).…”

Regulating Air‐Annealing Time for Boosting the Performance of Cu2ZnSn(S, Se)4 Solar Cells

“…Expect for Na, the prolonged annealing time makes less Cu and more Zn focus near the surface of films, which is profit to acquire the high-efficiency devices. [35][36][37] As the air-annealing time prolongs, SnO 2 phases can appear in the as-prepared film. In order to avoid the direct phase transformation to the SnSe 2 phase, [29] XRD patterns of the CZTSSe absorber layer with different air-annealing time need to be measured.…”

“…Expect for Na, the prolonged annealing time makes less Cu and more Zn focus near the surface of films, which is profit to acquire the high‐efficiency devices. [ 35–37 ]…”