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Covalent organic frameworks (COFs) have emerged as compelling interface optimizer candidates for competent perovskite solar cells (PSCs). However, there is a notable absence of rationally designed COFs tailored for perovskite and hole transporting layers (HTLs). Herein, an unreported one-dimensional (1D) triarylamine-based covalent organic framework (COF) {[(TPA)2(TPB)1]–C＝N–} with active amino groups was first synthesized. To anchor COF on the perovskite surface and manipulate the interface hole transportation, this 1D COF was salified with hydrogen halides to produce {[(TPA)2(TPB)1]–C＝N–-X} (COF-X; X = Cl, Br, and I). The ammonium terminals (–NH3+) can coordinate with perovskite via strong ionic interaction. The backbone units of triphenylamine (TPA) and N,N,N′,N′-tetraphenylbenzidine (TPB), renowned for their superior hole extracting and transporting properties, can enhance the hole mobility of the perovskite film from 1.02 to 3.72 cm2 V−1 s−1. Consequently, the optimal device achieved a power conversion efficiency (PCE) of 23.58% and an impressive open-circuit voltage (VOC) of 1.181 V. Additionally, the unencapsulated devices retained 90.8% and 89.2% of their initial efficiencies after atmospheric storage over 4800 hours and continuous illumination over 500 hours, respectively. [ABSTRACT FROM AUTHOR]

Two-dimensional CsPbBr3 nanoplates (NPLs) are highly promising blue emitters due to their precisely tunable emission wavelength by adjusting the thickness. However, synthesizing high-performance deep-blue emissive CsPbBr3 NPLs with fewer monolayers remains challenging. Here, multifunctional ligands of 2,6-diaminopyridinium hydrobromide (DaPyBr) with multiple coordination sites were designed and synthesized to attenuate the thickness of blue CsPbBr3 NPLs and suppress surface defects. DaPyBr serving both as a Lewis acid and a Lewis base possesses the dual functions of etching and passivation. It can detach the outer defect layers of CsPbBr3 NPLs reducing the thickness to 3 monolayers and passivate inner [PbBr6]4− layers suppressing the surface defects. Ultimately, CsPbBr3 NPLs treated by DaPyBr achieved a near-unity photoluminescence quantum yield at 456 nm. The target NPLs gained long-term storage stability and outstanding resistance to polar solvents. A bright deep-blue pattern display with commendable luminescence stability is achieved via aerosol printing technology. [ABSTRACT FROM AUTHOR]