Surface Capping Layer Prepared from the Bulky Tetradodecylammonium Bromide as an Efficient Perovskite Passivation Layer for High-Performance Perovskite Solar Cells

Abstract

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has increased and levels with silicon solar cells; however, their commercialization has not yet been realized because of their poor long-term stability. One of the primary causes of the instability of PSC devices is the large concentration of defects in the polycrystalline perovskite film. Such defects limit the device performance besides triggering hysteresis and device instability. In this study, tetradodecylammonium bromide (TDDAB) was used as a postsurface modifier to suppress the density of defects from the mixed perovskite film (CsFAMA). X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analyses validated that TDDAB binds to the mixed perovskite through hydrogen bonding. The X-ray diffraction (XRD) and two-dimensional grazing incidence wide-angle X-ray scattering (2D GIWAXS) study uncovered that the TDDAB modification formed a capping layer of (TDDA)2PbI1.66Br2.34 on the surface of the three-dimensional (3D) perovskite. The single charge transport device prepared from the TDDAB-modified perovskite film revealed that both the electron and hole defects were considerably repressed due to the modification. Consequently, the modified device displayed a champion PCE of 21.33%. The TDDAB surface treatment not only enhances the PCE but the bulky cation of the TDDAB also forms a hydrophobic capping surface (water contact angle of 93.39°) and safeguards the underlayer perovskite from moisture. As a result, the modified PSC has exhibited almost no performance loss after 30 days in air (RH ≈ 40%).

Organic Semiconductor Based on N, S‐Containing Crown Ether Enabling Efficient and Stable Perovskite Solar Cells

“…As shown in Figure S9d, the water contact angles of the control perovskite film, CDT‐S and CDT‐N treated perovskite films are 56.3°, 76.6°, and 72.2°, respectively. Apparently, the organic semiconductors CDT‐S and CDT‐N increase the water contact angle of perovskite films, which is of significance for the stability of perovskites [51,52] …”

“…Apparently, the organic semiconductors CDT-S and CDT-N increase the water contact angle of perovskite films, which is of significance for the stability of perovskites. [51,52] In this regard, the long-term stability of the device were further studied. As shown in Figure 8a, after stored in 1000 hours in ambient condition with a relative humidity of 30 % and a temperature of 25 °C, the efficiency of the control and CDT-S-treated unencapsulated devices retained 58 % and 90.5 % of the initial values, respectively.…”

Eco‐Friendly Solvent Engineered CsPbI2.77Br0.23 Ink for Large‐Area and Scalable High Performance Perovskite Solar Cells

“…The device fabrication procedures and fitting equations were adopted from the literature. [26] The trap density was calculated using Equation (3).…”

“…The device fabrication procedures and fitting equations were adopted from the literature. [ 26 ] The trap density was calculated using Equation (). $$$$\begin{equation}{N}_{{\mathrm{traps}}} = \frac{{2\varepsilon {\varepsilon }_0{V}_{{\mathrm{TFL}}}}}{{e{L}^2}}\end{equation}$$$$where N traps is the trap density, ɛ is the relative dielectric constant of CsPbI 3 , [ 31 ] ɛ 0 is vacuum permittivity, V TFL is trap‐filled limit voltage, e is the elementary charge, and L is the thickness of perovskite films.…”

“…Film/Device Characterizations: XRD, 2D-GIWAXS, FTIR, UPS, XPS, UV-vis absorption, PL, TRPL, Kelvin probe force microscopy KPFM, CPD, MPP, EIS, and SEM were employed to study the structural, morphological, and optoelectrical properties of the CsPbI 2.77 Br 0.23 films following the previous works. [26,32] Current density-voltage (J-V) and EQE of the perovskite devices were recorded using the same equipment and conditions employed in a previous work. [35] The active area of the devices was 0.1 cm 2 .…”