Two-dimensional (2D) perovskites have attracted considerable interest for their promising applications for solar cells and other optoelectronics, such as light-emitting diodes, spintronics, and photodetectors. Here, we review the recent achievements of 2D perovskites for various optoelectronic applications. First, we discuss the basic structure and optoelectronic properties of 2D perovskites, including band structure, optical properties, and charge transport. We then highlight recent achievements using 2D perovskites in solar cells and beyond solar cells, including progress on various synthesis strategies and their impact on structural and optoelectronic properties. Finally, we discuss current challenges and future opportunities to further develop 2D perovskites for various applications.

A new iodide layered double perovskite (C3H9NI)4AgBiI8 (IPBA) has been developed based on a short-chained spacer cation, which is the first homologous compound in iodide double perovskites that adopt the Ruddlesden-Popper structure type. Importantly, IPBA is a promising environmentally friendly alternative to recently rapidly progressing lead halide semiconductors owing to the narrow direct-bandgap of 1.87 eV and excellent stability.

A short peptide based hydrogel exhibits aqueous insolubility, thixotropy and efficient light induced syneresis. Upon irradiation with UV light, the hydrogel shrinks and expells ~ 50% of the solvent. Syneresis is caused by light-triggered trans-cis isomerisation of an azobenzene moiety in the peptide derivative. This expulsion of solvent can be effectively exploited in the removal of low molecular weight contaminants in water.

Intramolecular glycosylation strategy was used to synthesize a series of new glycoazobenzene macrocycles with high α-selectivity and interesting chiroptical property. The pho-toisomerization of azobenzene template influences mainly the efficiency of the glycosylation.

Nitroarenes are used as the coupling partner in the preparation of sulfonamides via the insertion of sulfur dioxide. A three-component reaction of arylboronic acids, nitroarenes, and potassium metabisulfite under copper catalysis proceeds smoothly, giving rise to a range of sulfonamides in good to excellent yields with broad substrate scope. Various functional groups including hydroxyl, cyano, amino, and carbonyl are all tolerated. A plausible mechanism is proposed, showing that arylsulfinate is the intermediate and the copper-assisted interaction of nitroarene and arylsulfinate is the key step. This approach is also extended to the late-stage modification of current marketed drug (Flutamide).

The one-step oxidation-mediated two-phase amplification system (OSO-TPAS) is applied firstly for sensitive detection of locus-specific 5hmC in DNA with little non-specific amplification. This strategy greatly shortens reaction time, improves sensitivity, reduces non-sepcific amplification and demonstrates enhanceds applicability.

Two 1,1,4,4‐tetracyanobutadiene (TCBD) derivatives were prepared by [2+2]cycloaddition‐retroelectrocyclization from ynamides bearing either a pyrene (1) or a perylene unit (2). In addition to panchromatic absorptions in 2, in the solid state, both compounds unexpectedly display NIR photoluminescence that could be detected up to about 1350 nm.

Peptide-targeting probes tagged with optical imaging and PET reporters may find application in innovative diagnostic procedures as well as in imaging-guided surgery. The reported synthesis procedure is of general applicability to obtain dual imaging probes using fully unprotected moieties with a selective and rapid chemistry based on the native chemical ligation

A new kind of oxygen-rich carbon microspheres with nanoflakes-interlaced architecture has been successfully prepared by a facile surfactant-assisted precipitation polymerization method. This hierarchical infrastructure can efficiently buffer the volume change during the potassiation/depotassiation cycles.

Isosmaragdyrin with N3C2 core is successfully achieved by introducing a 2,6-Di-m-phenylpyridine unit. The core is utilized to stabilize Rh(I) ion with N-Rh(I)-N bonding mode and Pt(II) ion with (N^C)N fashion to form an unsymmetrical pincer type organometallic complex.