Herein, γ-AlO(OH) as an inorganic was successfully inserted into MgAl-LDH layer by a one-pot synthesis, the composite as an adsorbent for removing methyl orange (MO) from wastewater. The structure and adsorption performance of γ-AlO(OH)/MgAl-LDH were characterized. The research shows that the expansion (003) plane and the hydroxyl active site of γ-AlO(OH)/MgAl-LDH can promote adsorption capacity and adsorption kinetics, respectively. Therefore, γ-AlO(OH)/MgAl-LDH exhibits a super adsorption performance, which completely adsorbs MO at the concentration of 1000 mg g −1 . In addition, the maximum adsorption capacity of MO was 4681.40 mg g −1 according to the Langmuir model. These results indicate that γ-AlO(OH)/MgAl-LDH is a potential adsorbent for the removal of organic dyes in water.

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In this study, a new type of 0-dimensional organic–inorganic hybrid perovskite single crystal (2-5-py)2MnBr4 was synthesized using 2-amino-5-methylpyridine (2-5-py) as the organic ligand. The crystal is a center-symmetric P-1 space group with a grain size of 20 mm, which belongs to the triclinic crystal system. It has a strong absorption of violet and blue light as well as excellent thermal stability. Its optical band gap is 2.38 eV, which is in good agreement with the theoretical band gap (2.39 eV) calculated by density functional theory. Under the excitation of a suitable light source, it can emit 526 nm pure bright green lights, which are confirmed by the main peaks to be almost in the green range with a full width at half maximum of 45 nm. As a result, the quantum efficiency and fluorescence lifetime reached a high level of 44.2% and 117 μs, respectively. Based on the good fluorescence performance of the crystal, a white LED with a color rendering index of 97 was finally successfully fabricated, realizing the leap from basic materials to optoelectronic devices.

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role in the efficient extraction and transport of charge carriers. [6][7][8] At present, 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-MeOTAD) is the most widely used HTM for PSCs in laboratory studies. [9][10][11][12][13] However, it may not be suitable to be developed for mass production due to its high material cost and deliquescent additives. [14][15][16][17][18] Compared with organic HTMs, inorganic HTMs exhibit advantages of improved chemical stability, higher hole mobility, and lower production cost. Therefore, the development of inorganic HTMs is an alternative and essential strategy for the commercialization of PSCs. [19][20][21][22][23][24][25][26][27][28] Cuprous thiocyanate (CuSCN) has been reported to be one of the most promising inorganic HTMs with high hole mobility, excellent chemical stability, and ideal energy level alignment with perovskites. [29][30][31][32][33][34][35][36][37][38] However, compared with the devices using spiro-OMeTAD, the PSCs based on CuSCN show relatively poor photovoltaic performance, which is mainly due to the decomposition of underlying perovskites layer by polar solvents for dissolving CuSCN such as diethyl sulfide (DES), dipropyl sulfide, etc. [39][40][41][42] These solvents lead to a surface contact damage to perovskites due to their strong polarity. As a result, surface voids acting as traps for capturing charge carriers are very likely to form at the perovskite/CuSCN interface. [43] In Cuprous thiocyanate (CuSCN) is an ideal inorganic hole transport material for perovskite solar cells (PSCs). However, polar solvents for film deposition of CuSCN run a risk of destroying the perovskite light-absorbing layer. There is also a poor contact between perovskites and CuSCN, restricting photovoltaic performance and operational stability of PSCs. In this work, a polyethylene glycol (PEG-10000) is employed as an interlayer to effectively overcome the obstacles mentioned above. By introducing this ultra-thin layer at the interface between (MAFA)Pb(IBr) 3 and CuSCN, the power conversion efficiency (PCE) and operational stability of the related PSCs are both greatly improved. The results confirm that the insertion of PEG cannot only prevent the destruction of bulk perovskites but also reduce the traps/defects at the interface through its strong chemical bonding with undercoordinated ions, which significantly lowers the potential barrier between the perovskite and the hole transport layer. An improved PCE of 19.2% can be achieved in the CuSCNbased PSCs by interface engineering with PEG. The introduction of PEG can also protect the perovskite film from moisture attack, and greatly enhance device stability. The PEG-treated PSCs without encapsulation maintain more than 90% of the initial efficiency after 1860 h in the ambient air.