Efficient Trap Passivation of MAPbI₃ via Multifunctional Anchoring for High‐Performance and Stable Perovskite Solar Cells

Abstract

Chemical passivation of ionic defects in perovskite materials is an effective strategy to reduce charge recombination in perovskite solar cells (PSCs). Although several additives have been used for this purpose, the passivation mechanisms of different functional groups have remained unclear. Herein, the effect of molecules possessing multiple functional anchoring is systematically investigated. Three different multifunctional molecules namely 5‐aminoisophthalic acid (AIA), 5‐hydroxyisophthalic acid (HIA), and chelidamic acid (CA) are strategically chosen. These molecules not only take part in the crystallization process but also passivate the trap states effectively. CA shows superior passivation capacity among all with a better dipolar electron density distribution. The passivated films have considerably improved morphology with fewer pin holes, larger grains, and lower trap states in comparison to the pristine film. CA‐passivated p–i–n structured photovoltaic devices demonstrate the best power conversion efficiency (PCE) of 19.06% with an impressive open circuit voltage (VOC) of 1.097 V, whereas pristine devices show a PCE of 13.60% and VOC of 0.972 V. Moreover, the modified device reveals notable thermal and ambient stability in comparison to the pristine device due to lower defect states and reduced ion migration.

The disappearing additive: introducing volatile ethyl acetate into a perovskite precursor for fabricating high efficiency stable devices in open air

“…The combination of R ct and CPE relates to the high-frequency arc in the impedance spectra, which is associated with the charge transport resistance at heterojunction interface and associated capacitance. 46,47 These results determine the fact that the interfacial combination is remarkably suppressed by applying EA, and the suppressed electron-hole recombination can efficiently improve the V oc of PSCs. To deeply understand the defect states of PSCs, the space charge limited current (SCLC) measurements were employed and the data is revealed in Fig.…”

“…The combination of R ct and CPE relates to the high-frequency arc in the impedance spectra, which is associated with the charge transport resistance at heterojunction interface and associated capacitance. 46,47 Table 3 lists the equivalent circuit of corresponding parameters. Lower R s and higher R ct are realized for EA-modified perovskite film-based PSC, suggesting the more efficient charge transfer at the interfaces during device work.…”

CsPbBr3 Nanocrystal Induced Bilateral Interface Modification for Efficient Planar Perovskite Solar Cells

“…[ 6 , 7 ] These defects serve as recombination sites for photogenerated electrons and holes, causing the loss of the effective carriers. [ 8 ] In addition, the defects are highly sensitive to moisture, heat, oxygen, and ultraviolet light, leading to decomposition of the perovskite. [ 9 , 10 ] Therefore, defect control is crucial for fabrication of PSCs with high efficiency and long‐term stability.…”

Improved Nanophotonic Front Contact Design for High‐Performance Perovskite Single‐Junction and Perovskite/Perovskite Tandem Solar Cells

“…Perovskite solar cells (PSCs) are considered as an alternative to the present silicon (Si) photovoltaic (PV) technology because they can materialize the most attractive advantages of third-generation thin-film photovoltaics. [1][2][3][4][5][6][7][8] Both the academic and industrial communities are intrigued by the PSCs due to their unique combination of desirable properties and ease of fabrication as they offer high absorption, tunable bandgap, low deposition temperature, and long carrier diffusion length, while using an inexpensive and scalable solution process to fabricate PSCs. [9][10][11][12][13] At a basic level, the large carrier diffusion lengths >1 μm combined with the short penetration depth of light (≤0.4 μm) results in thin-film solar cells with high power conversion efficiency (PCE).…”

“…[3,9] To date, several metal oxides, such as ZnO, TiO 2 , and SnO 2 , are used as ETLs to fabricate efficient PSCs with greater device stability. [7,18,22,23] However, most high-efficiency perovskite photovoltaic devices utilize TiO 2 as ETL due to its high electron mobility, better environmental stability, favorable energy level, smooth surface coverage, and most importantly, low-cost deposition process. [18,24,25] This study focuses on designing efficient structured front contacts for PSCs with enhanced photon absorption by photon management optimization and improved electrical performance by efficient charge extraction.…”