Deep‐Ultraviolet Photoactivation‐Assisted Contact Engineering Toward High‐Efficiency and Stable All‐Inorganic CsPbI₂Br Perovskite Solar Cells

Abstract

All‐inorganic perovskite CsPbI2Br have been regarded as a promising candidate to tackle the thermal instability issue of organic–inorganic perovskite solar cells. However, the serious interfacial charge recombination and large voltage potential loss in cells circumscribe their performance and commercialization. Herein, a facile approach is demonstrated in which the SnO2 electron transport layer is modified with short‐period deep‐ultraviolet (DUV) photoactivation process to decrease the work function and achieve better energy alignment with the conduction band of perovskites. Such modification triggers efficient charge transfer and reduces the charge recombination. Moreover, first‐principles calculation further demonstrates that DUV‐treated SnO2 can strengthen the interface interaction, reduce the interface stress caused by lattice mismatch, induce more ordered perovskite structure, enlarge transfer charge from 0.71 to 2.33 e, gain larger built‐in field (from 0.74 to 2.09 eV), lower work function, and smaller conduction band offset. Thus, all‐inorganic CsPbI2Br solar cells based on DUV‐treated SnO2 exhibit a significant enhancement in power conversion efficiency, and the champion cell achieves an elevated efficiency of 15.1% with a superior Voc of 1.22 V and better stability.

5‐Chloroindole as Interface Modifier to Improve the Efficiency and Stability of Planar Perovskite Solar Cells

“…[8,10,11] Notwithstanding, defects and oxygen vacancies occurred during the preparation of SnO 2 thin films, which led to the generation of nonradiative recombination and deteriorated the PV performance of the device. [12][13][14][15][16] Therefore, the modification of SnO 2 ETL has become a hot topic today.…”

S8 Additive Enables CsPbI2Br Perovskite with Reduced Defects and Improved Hydrophobicity for Inverted Solar Cells

“…For solution‐processed inorganic perovskite film, primary defects including uncoordinated Pb 2+ ions, halogen vacancies, Pb 0 /I 0 clusters and PbI 3 − antisite defects may act as carrier traps, leading to charge recombination loss and consequently reduced device performance. [ 20–23 ] In addition, the defects at grain boundaries (or interface) are vulnerable to moisture corrosion, resulting in phase deterioration and device degradation. [ 20 ] Hence, how to efficiently reduce defect density and hinder moisture corrosion is highly concerned for inorganic perovskite, especially for CsPbI 2 Br.…”

An Exploration of All‐Inorganic Perovskite/Gallium Arsenide Tandem Solar Cells

“…In the simulation of 4-T all-inorganic perovskite/GaAs tandem solar cells, CsPbI 2 Br is chosen as all-inorganic perovskite in the top cell due to its suitable bandgap and high PCE as an independent subcell. [30][31][32][33][34] As shown in Figure 1a, the SnO 2 electron transport layer (ETL) and organic HTL are used as parts of the high-performance inorganic PSCs. As the electrical and optical parameters of organic HTLs, such as poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2 0 ,7,7 0 -Tetra(N,N-di-p-tolyl) amino-9,9-spirobifluorene (spiro-TTB), and 2,2 0 ,7,7 0 -Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9 0 -spirobifluorene (spiro-OMeTAD), are similar, this study takes spiro-OMeTAD as an example.…”

“…As the electrical and optical parameters of organic HTLs, such as poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2 0 ,7,7 0 -Tetra(N,N-di-p-tolyl) amino-9,9-spirobifluorene (spiro-TTB), and 2,2 0 ,7,7 0 -Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9 0 -spirobifluorene (spiro-OMeTAD), are similar, this study takes spiro-OMeTAD as an example. [24,[34][35][36] To explore the performance characteristics of perovskite/GaAs solar cells and economize materials as much as possible, the first step is to determine the optimal thicknesses of the absorbing layers in the top cell and bottom cell. The parameters of the CsPbI 2 Br top cell and GaAs bottom cell in the simulation are summarized in Table 1 and 2, respectively.…”