Orbital Interactions between the Organic Semiconductor Spacer and the Inorganic Layer in Dion–Jacobson Perovskites Enable Efficient Solar Cells

Abstract

2D Dion–Jacobson (DJ) perovskites have become emerging photovoltaic materials owing to their intrinsic structure stability. However, as insulating aliphatic cations are widely used as spacers, the interactions between the spacers and inorganic layers in DJ perovskites have rarely been studied. Here, an organic semiconductor spacer with two covalently connected thiophene rings, namely bithiophene dimethylammonium (BThDMA), is successfully developed for 2D DJ perovskite solar cells (PSCs). An important finding is that there are strong orbital interactions between the conjugated organic spacer and adjacent inorganic layers, whereas no such interactions exist in DJ perovskite using an aliphatic octane‐1,8‐diaminium (ODA) spacer with similar length. The BThDMA spacer with multiple conjugated aromatic rings can also induce crystal growth with large grain size and preferred vertical orientation, resulting in reduced trap density and improved charge‐carrier mobility. As a result, the optimized device based on (BThDMA)MAn−1PbnI3n+1 (nominal n = 5) shows an excellent PCE of 18.1% with negligible hysteresis, which is a record efficiency for 2D DJ PSCs using a spacer with two or more covalently linked aromatic rings. These findings provide a novel and important insight on achieving efficient and stable 2D DJ perovskite solar cells by developing organic semiconductor spacers.

Solvent bath annealing-induced liquid phase Ostwald ripening enabling efficient and stable perovskite solar cells

“…The higher relative intensity of the (110) plane in the SBA-treated film suggests a preferable orientation of the perovskite crystals. 40,49 In addition, the peak at 2 θ = 12.8° attributed to the excess PbI 2 in the perovskite films disappears from the SBA-treated film, which is also consistent with the SEM observations. 31 Bright plate-shaped particles are observed at the grain boundaries of the TA- and SVA-treated films, which can be attributed to the residual PbI 2 in the perovskite films (Fig.…”

Defect Regulation of Efficient Dion–Jacobson Quasi-2D Perovskite Solar Cells via a Polyaspartic Acid Interlayer

“…The ratio of intensity for (202) and (111) planes ( I (202) / I (111) ) is 0.88 for perovskite films without PASP interlayer modification, which is smaller than that for perovskite films modified by PASP. The result implies that the layered phases in perovskite films modified with PASP are easier to grow perpendicular to the substrate. , A maximum value of 1.04 for I (202) / I (111) is achieved at 0.1 mg/mL, suggesting the optimal film orientation of 2D perovskites. The dependence of full width at half-maximum (FWHM) of (111) and (202) planes on PASP concentration is demonstrated in Figure b.…”

Recent advances on two-dimensional metal halide perovskite x-ray detectors

“…Huang et al [40] studied the in-plane conductivity of the quasi-2D (BA) 2 (MA) 2 Pb 3 I 10 (n = 3) single crystals (SCs) at varied temperatures. Compared to 3D perovskites, which show a clear electronic to ionic conductivity transition at 280 K both in the dark and under illumination, the quasi-2D (BA) 2 (MA) 2 Pb 3 I 10 perovskite samples are absent of such conductivity transition up to 350 K. Moreover, 2D perovskites are endowed with superior humidity stability [41][42][43], structural stability [44][45][46], and thermal stability [47][48][49] due to the hydrophobic nature of organic cations and strong van der Waals forces between the organic layers.…”