Wearable Tin‐Based Perovskite Solar Cells Achieved by a Crystallographic Size Effect

Abstract

Tin‐based perovskite solar cells (PSCs) demonstrate a potential application in wearable electronics due to its hypotoxicity. However, poor crystal quality is still the bottleneck for achieving high‐performance flexible devices. In this work, graphite phase‐C3N4 (g‐C3N4) is applied into tin‐based perovskite as a crystalline template, which delays crystallization via a size‐effect and passivates defects simultaneously. The double hydrogen bond between g‐C3N4 and formamidine cation can optimize lattice matching and passivation. Moreover, the two‐dimensional network structure of g‐C3N4 can fit on the crystals, resulting an enhanced hydrophobicity and oxidation resistance. Therefore, the flexible tin‐based PSCs with g‐C3N4 realize a stabilized power conversion efficiency (PCE) of 8.56 % with negligible hysteresis. In addition, the PSCs can maintain 91 % of the initial PCE after 1000 h under N2 environment and keep 92 % of their original PCE after 600 cycles at a curvature radius of 3 mm.

Defect Passivation with Metal Cations toward Efficient and Stable Perovskite Solar Cells Exceeding 22.7% Efficiency

“…Liu et al 13 incorporated an ionic liquid into the triple-cation FAMACs perovskite to improve its crystallization and passivate perovskite defects, showing a champion PCE of over 21.4% and excellent stability more than 92% of its initial efficiency after 1200 h under continuous illumination at 70−75 °C. Chen et al 16 employed 2D g-C 3 N 4 to passivate the surface and grain boundary of tin-based perovskites and obtained a high-quality film with strong hydrophobicity and oxidation resistance. Therefore, the tin-based PSCs via g-C 3 N 4 passivation showed high PCE and long-term stability.…”

“…The chemical formula of halide perovskites is ABX 3 , where sites A, B, and C are occupied by monovalent cations, divalent metal cations, and monovalent halogen anions, respectively. Although the perovskite has a strong tolerance ability, defects have been the key factors dragging PCE and stability of PSCs. , Passivators, such as Lewis base/acid, − ionic liquids, − and low-dimensional materials, − can solve this problem by passivating defects in perovskites for PSCs. For example, Jen et al used a Lewis base small molecule (6TIC-4F) to passivate the defects on the surface/grain boundaries of the CsPbI x Br 3‑x perovskite film.…”

Scalable Flexible Perovskite Solar Cells Based on a Crystalline and Printable Template with Intelligent Temperature Sensitivity

“…By fitting 2θ as a function of sin2φ, the residual stress in the perovskite films can be estimated from the slope of the fitting line. [38,40,41] Figure 3a-b and S15, Supporting Information, show the XRD patterns of the (222) crystal plane in the reference film, 6OBA-incorporated film, and 5CB-incorporated film. By varying Ψ from 10 to 50 , the diffraction peaks gradually shifted to smaller degrees, indicating the increase of crystal plane distance d (222) .…”

“…[ 36 ] In addition, the characteristic 1 H NMR peaks of MAPbI 3 shifted to a low field in the 6OBA‐incorporated film, manifesting a deshielding effect (Figure S14, Supporting Information). [ 37–39 ] The deshielding effect on the hydrogen of MA + can enhance the performance of F‐PSCs.…”

Flexible Perovskite Solar Cells with High Power-Per-Weight: Progress, Application, and Perspectives

“…The efficiency issue is mainly derived from poor crystallinity of the perovskite films, while the instability issues mainly originate from both material and device aspects, particularly referring to the intrinsic thermodynamic stability of Sn 2+ cation and interfacial energy level alignment for stratified PSCs. Inspired by the crystallographic size effect of antifreeze proteins, Rao et al 149 applied graphite-phase C 3 N 4 (g-C 3 N 4 ) as a crystalline template to delay the crystallization process and simultaneously passivate the defects. It was demonstrated that the similar distances between atoms facilitated the formation of double hydrogen bonds, and then the similarity in value of the In comparison to heavier drones, miniature unmanned aerial vehicles with low-mass at the order of several hundred milligrams or less have extremely low kinetic energy and greater safety during flight.…”