Ultrawide Band Gap Oxide Semiconductor-Triggered Performance Improvement of Perovskite Solar Cells via the Novel Ga₂O₃/SnO₂ Composite Electron-Transporting Bilayer

Abstract

The performance of perovskite solar cells (PSCs), especially for the parameters of open-circuit voltage (V oc ) and fill factor, is seriously restricted by the unavoidable interfacial charge recombination. In this study, an ultrawide band gap semiconductor material of Ga 2 O 3 is introduced between fluorine-doped tin oxide and SnO 2 to regulate the interfacial charge dynamics by forming the Ga 2 O 3 /SnO 2 electron-transporting bilayer. Ga 2 O 3 has an appropriate conduction band minimum which benefits the electron transport, and at the same time, it has a very deep valence band maximum which could be regarded as an effective blocking layer. Such an innovative structure triggers the advantages of a lower work function and a smoother surface of the electron-transporting bilayer which leads to a high-quality perovskite film. Furthermore, superior hole-blocking properties of the introduced Ga 2 O 3 layer could effectively reduce the interfacial recombination. All the properties could help to improve the extracting and transporting ability of charge carriers synergistically. Finally, the efficiency and stability of PSCs are greatly enhanced. All results suggest that the performance of PSCs could be improved effectively by introducing the ultrawide band gap oxide semiconductor of Ga 2 O 3 .

Interfacial Dipole poly(2-ethyl-2-oxazoline) Modification Triggers Simultaneous Band Alignment and Passivation for Air-Stable Perovskite Solar Cells

“…The aforementioned factors act as a guideline for optimizing PSCs in terms of developing efficient interlayer materials and feasible interfacial engineering through surface passivation that contributes to suppressing the structural defects and improving the quality and chemical stability of perovskite films, which can further help to eliminate the interfacial energy barriers, reduce trap density and nonradiative recombination loss at interfaces, and thus enhancing the transport and extraction ability of charge carriers at the interfaces, targeting to top cell efficiency [32,33]. More recently, various successful interface modification strategies have been proposed and were concerned with solving the above obstacles, which produced a large number of emerging interfacial modifier materials including organic halide salt, i.e., phenylethylammonium iodide (PEAI), phenylmethylamine iodide (PMAI), butylammonium iodide (BAI) and 1-naphthylmethylamine iodide (NMAI) [34][35][36], organic molecules with specific functional groups [37][38][39][40][41], twodimensional materials [42][43][44] and others [45][46][47] capable to adjust the interface dynamics of charge carriers in PSCs and ultimately boost device performance and operational stability. Among these materials, the dipole molecules, such as poly(2-ethyl-2-oxazoline) (PEOz), polyethoxyvinylimine (PEIE) and polyethyleneimine (PEI), have aroused enough attention because of their versatility and ease to operate features.…”

Scalable Preparation of High‐Performance ZnO–SnO2 Cascaded Electron Transport Layer for Efficient Perovskite Solar Modules

“…However, the commonly used low‐temperature sol–gel processed amorphous SnO 2 film is very demanding on the fabrication environment humidity, temperature, and annealing ambient, [ 15 ] thus leading to great uncertainty in its crystal quality, film morphology, and relative electronic properties. Accordingly, numerous efforts have been made to construct the bilayer ETL based on SnO 2 to obtain the desired significantly improved electron extraction performance with controllable morphology for efficient PSCs, e.g., TiO 2 /SnO 2 , [ 16 ] SnO 2 /Sb‐SnO 2 , [ 17 ] Ga 2 O 3 /SnO 2 , [ 18 ] In 2 O 3 /SnO 2 , [ 19 ] MgO/SnO 2 , [ 20 ] PCBM/SnO 2 , [ 21 ] ZnO/SnO 2 , [ 22 ] and ZnO@SnO 2 . [ 23 ] Among these strategies, the ZnO–SnO 2 composite ETL shows the most attractive properties as an excellent ETL material, including the reliable interface stability, better electron mobility, and superior charge extraction.…”

Low Temperature Producing Copper‐Doped Gallium Oxide as Hole Transport Layers of Perovskite Solar Cells Enhanced by Impurity Levels

“…[ 34 ] Ga 2 O 3 can also improve the performance of conventional electron transport layers, such as SnO 2 and PCBM. [ 35,36 ] However, Ga 2 O 3 was not yet reported as hole transport layers of PSCs on account of the large mismatched valence bands between Ga 2 O 3 layers and perovskite layers. Previous literatures report that Sn or Si dopants can provide additional conduction channels in Ga 2 O 3 by the impurity levels.…”