Beneficial Role of Organolead Halide Perovskite CH₃NH₃PbI₃/SnO₂ Interface: Theoretical and Experimental Study

Abstract

Understanding the interfacial properties of perovskite/SnO2 interface is important for perovskite solar cell design and optimization. Here, interfacial structure and transport properties of CH3NH3PbI3/SnO2 interfaces are investigated comprehensively by density functional theory and experiment. Forming CH3NH3PbI3/SnO2 interfaces weakens the gap states induced by CH3NH3PbI3 surfaces. The interfacial transport properties are strongly dependent on the interface atomic configurations. The CH3NH3PbI3/SnO2 interface with PbI and O terminations is more beneficial for hole blocking and electron transporting due to the largest valence band offset compared to the CH3NH3PbI3/SnO2 interface with other terminations. Moreover, it exhibits a larger electrostatic potential difference compared with CH3NH3PbI3/TiO2 interface, leading to the higher electron transfer efficiency. Hence, higher power conversion efficiency is achieved based on CH3NH3PbI3/SnO2 compared to CH3NH3PbI3/TiO2 structure in experiments. In addition, CH3NH3PbI3/SnO2 interfaces with PbI terminations are more stable than those with CH3NH3I terminations, suggesting PbI2 layer may be preferentially formed on SnO2 substrate during CH3NH3PbI3 fabrication process. Such results could provide a useful understanding on CH3NH3PbI3/SnO2 interface and contribute to new strategies for the interface optimization.

Enhancing Perovskite Solar Cell Performance through Surface Engineering of Metal Oxide Electron-Transporting Layer

“…The decreased work function would result in better energy level alignment and more efficient electron transfer between the conduction band of perovskite and the Fermi level of ETL. Moreover, the potential difference between two electrode contacts, such as TiO 2 and spiro-OMeTAD, was also enlarged due to the decreased work function, hence increasing the V oc of the device [33].…”

“…Hence, various interface transporting layers have been studied. Among them, metal oxides (e.g., ZnO, SnO 2 , and TiO 2 ) have been widely investigated as electron-transporting layers (ETLs) in PSCs [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37], particularly TiO 2 ETL. The surface and electronic properties of TiO 2 play important roles in determining the final device performance, including power conversion efficiency (PCE), hysteresis behavior, and stability [20,38,39].…”

High Performance Planar Structure Perovskite Solar Cells Using a Solvent Dripping Treatment on Hole Transporting Layer

“…Coatings 2019, 9, x FOR PEER REVIEW 2 of 10 hydrophobic properties or using inorganic NiO HTL to replace PEDOT:PSS film become more important [23,25,26,[31][32][33][34]. Previously, in organic solar cells and perovskite solar cells, some polar solvents including ethylene glycol (EG), dimethyl sulfoxide (DMSO), dopamine, F4-TCNQ, dimethyl formamide (DMF), imidazole, etc.…”

“…The perovskite solar cell (PSC) has received significant attention because of their unique properties such as high power conversion efficiency, simple solution processibility, high balanced charge carrier mobility, and intense light absorption [1][2][3][4][5][6][7][8][9]. In the past few years, the highest device power conversion efficiency (PCE) has been rapidly increased from 3.8% up to over 24% [10][11][12][13][14], and this PCE can be further improved by applying proper interface engineering, solvent engineering and composition engineering approaches [5,[15][16][17][18][19][20][21][22][23][24][25][26][27][28].…”

“…Even so, ascribed to the acidic and hydrophilic nature of PEDOT:PSS interlayer, poor stability and inefficient charge extraction/collection have become the challenging issues. Hence, proper methods to enhance the PEDOT:PSS conductivity and hydrophobic properties or using inorganic NiO HTL to replace PEDOT:PSS film become more important [23,25,26,[31][32][33][34].…”