Dimension-Controlled Growth of Antimony-Based Perovskite-like Halides for Lead-Free and Semitransparent Photovoltaics

Abstract

Antimony (Sb) has been identified as a promising candidate for replacing toxic lead (Pb) in perovskite materials because Sb-based perovskite-like halides exhibit not only intrinsic thermodynamic stability but also a unique set of intriguing optoelectronic characteristics. However, Sb-based perovskite-like halides still suffer from poor film morphology and uncontrollable halide constituents, which result from the disorder of the growth process. Herein, we propose a simple strategy to facilitate heterogeneous nucleation and control the dimension transformation by introducing bis­(trifluoromethane)­sulfonimide lithium (LiTFSI), which produces high-quality two-dimensional MA3Sb2I9–x Cl x films. As the spacer molecule among Sb-based pyramidal clusters, LiTFSI plays a role in forming a zero-dimensional intermediate phase and retarding crystallization. The slower dimension transformation well stabilizes the band gap of perovskite-like films with a fixed Cl/I ratio (∼7:2) and avoids random “x” values in MA3Sb2I9–x Cl x films prepared from the conventional method. Based on this method, Sb-based perovskite-like solar cells (PLSCs) achieve the highest recorded power conversion efficiency (PCE) of 3.34% and retain 90% of the initial PCE after being stored under ambient conditions for over 1400 h. More importantly, semitransparent Sb-based PLSCs with PCEs from 2.62 to 3.06% and average visible transparencies from 42 to 23% are successfully obtained, which indicates the great potential of the emerging Pb-free halide semiconductor for broad photovoltaic applications.

Hierarchically Designed Light Trapping Films for All‐Day Operating Semitransparent Photovoltaics

“…The device with double‐sided hierarchical films acted as a nearly black absorber, while the bare counterpart device was visibly transparent. Light trapping ability of the hierarchical films was also confirmed with the average visible transmittance (AVT) and the visible light transmittance (VLT) values obtained from transmittance spectra of ST‐OPVs (Figure S16, Supporting Information) [ 34,38 ] and these values are plotted in Table S2 in the Supporting Information. The AVT and VLT values were further reduced when the double hierarchical films were attached on both top and bottom sides; this observation implies a feasibility of the hierarchical film for high‐efficiency bifacial photovoltaics.…”

2D‐MA3Sb2I9 Back Surface Field for Efficient and Stable Perovskite Solar Cells

“…As shown in Figure S1 (Supporting Information), the main peaks at ≈17°, 25.2°, and 29.5° are (002), (003), and (022) planes of 2D‐MA 3 Sb 2 I 9 , respectively. [ 33,34 ] The two‐step fabrication verifies that 2D‐MA 3 Sb 2 I 9 can be grown on MAPbI 3 by SbI 3 reacting with the MA group on MAPbI 3 surface. In our density functional theory (DFT) calculation, it is noticed that a high‐quality and intimate MAPbI 3 /MA 3 Sb 2 I 9 interface can only be constructed by stacking (101) MAPbI 3 and (001) 2D‐MA 3 Sb 2 I 9 slabs together, with a lattice mismatch of <5% (Figure S2, Supporting Information).…”

Defect Suppression in Oriented 2D Perovskite Solar Cells with Efficiency over 18% via Rerouting Crystallization Pathway

“…Space charge‐limited current (SCLC) technique was used to characterize the electrical properties of 2D perovskite films. [ 13,33,34 ] The trap density calculated from the trap fill‐in limit voltage was found to decrease from 5.05 × 10 15 cm −3 for the RCP‐2D film to 4.52 × 10 15 cm −3 for the reference (Figure 4g). The hole mobility of the RCP‐2D film (7.76 × 10 −3 cm 2 V −1 s −1 ) was about threefold higher than the reference film (2.98 × 10 −3 cm 2 V −1 s −1 ).…”