24.20%‐Efficiency MA‐Free Perovskite Solar Cells Enabled by Siloxane Derivative Interface Engineering

Abstract

Suppressing defects at the interface between the TiO2 electron transport layer (ETL) and perovskite film is critical for high efficiency and stable perovskite solar cells (PSCs). Herein, a siloxane derivative diethylphosphatoethylsilicic acid (PSiOH) is developed to modify the interface of TiO2 ETL/FA0.83Cs0.17PbI3 perovskite. Comprehensive characteristics reveal that silicon hydroxyl (SiOH) in PSiOH can reduce surface defects, improve the electrical properties and optimize the energy band structure of TiO2 by forming a SiOTi bond, while the phosphate bond (PO) in PSiOH can passivate Pb‐related defects on the perovskite bottom surface. Consequently, PSiOH‐modified PSCs yield a remarkable power conversation efficiency of 24.20% and improved air, thermal, or illumination stabilities. This study provides insight into passivation defects at the buried interface for efficient and stable PSCs.

24.96%‐Efficiency FACsPbI3 Perovskite Solar Cells Enabled by an Asymmetric 1,3‐Thiazole‐2,4‐Diammonium

“…[40] As shown in Figure 1g, the electron mobility is obviously increased from 6.49 × 10 −4 to 1.18 × 10 −3 cm 2 V −1 s −1 after TDA modification. In addition, the conductivity is tested (Figure 1h), [18] which is significantly enhanced from 2.42 × 10 −3 to 3.99 × 10 −3 mS cm −1 after TDA modification. The enhanced mobility and conductivity of SnO 2 / TDA film suggests that TDA modification is beneficial for the electron extraction and transport.…”

“…[7][8][9][10][11][12][13] Replacing some FA + with cesium (Cs + ) to construct FACsPbI 3 perovskite is an effective avenue to achieve phase-stable PSCs due to its suitable Goldschmidt's tolerance factor (close to the optimal range "0.9-1"). [14,15] The PCE of FACsPbI 3 PSCs has rocked up over 24% with the help of the crystal growth regulation, [16] interface/ bulk defect passivation, [17,18] and device fabrication engineering. [19] However, the PCE of FACsPbI 3 PSCs is still lower than that of FAPbI 3 PSCs because the unmatched ion sizes and different crystallization dynamics of FA + and Cs + lead to the poor composition homogeneity, large lattice distortion, and high trap-defect densities for FACsPbI 3 perovskite film.…”

Minimized Energy Loss at the Buried Interface of p‐i‐n Perovskite Solar Cells via Accelerating Charge Transfer and Forming p–n Homojunction

“…The capacitance–voltage ( C–V ) measurements are proceeded under dark condition to investigate the charge carrier trapping and accumulating behavior at the HTL/perovskite interfaces for p‐i‐n PVSCs based on different PTAA and Poly‐TPD HTLs according to the Mott–Schottky equation expressed as $$\frac{1}{{{C^2}}} = \frac{{ - 2}}{{{\varepsilon _0}\varepsilon q{A^2}N}}(V - {V_{{\rm{bi}}}})$$, where the A , N , and V represent the active area of device, free carrier concentration, and applied bias. [ 39 ] The C −2 – V curves are shown in Figure 6d and the corresponding V bi values are listed in Table S9, Supporting Information. The p‐i‐n PVSCs based on both the AMD treated PTAA and Poly‐TPD HTLs exhibit much larger V bi than those based on the pristine or CMD treated HTLs, which is because the AMD strategy can reduce the energy level offset by forming p–n homojunction at the HTL/perovskite buried interface, thereby enhancing the V bi of the corresponding p‐i‐n PVSCs.…”

“…, where the A, N, and V represent the active area of device, free carrier concentration, and applied bias. [39] The C −2 -V curves are shown in Figure 6d and the corresponding V bi values are listed in Table S9, Supporting Information. The p-i-n PVSCs based on both the AMD treated PTAA and Poly-TPD HTLs exhibit much larger V bi than those based on the pristine or CMD treated HTLs, which is because the AMD strategy can reduce the energy level offset by forming p-n homojunction at the HTL/perovskite buried interface, thereby enhancing the V bi of the corresponding p-i-n PVSCs.…”

Solvent-Assisted Crystallization of an α-Fe2O3 Electron Transport Layer for Efficient and Stable Perovskite Solar Cells Featuring Negligible Hysteresis

“…In the state-of-the-art n–i–p PSCs, metal oxide (MO X ) semiconductor TiO 2 -, ZnO-, SnO 2 -, Nb 2 O 5 -, CeO x - , Cr 2 O 3 -, Fe 2 O 3 -, and WO 3 -based ETLs remain a preferred choice. − TiO 2 and SnO 2 are the most frequently applied ETLs, and solar cells based on these have demonstrated PCEs approaching 25%. − The TiO 2 ETL is known for its defect-rich surface and also leads to degradation in PSCs upon exposure to UV illumination hampering the device operational stability. , The TiO 2 ETL also requires a high annealing temperature exceeding 500 °C, which hinders its application in mass production. SnO 2 ETLs can be processed at low temperatures and offer a high mobility, wide band gap, and superior stability than the TiO 2 counterpart.…”