Novel fluorene-based bis-tridentate Ir(iii) phosphors are capable of exhibiting both improved stability and efficient deep-blue emission in solution.

Spiro-OMeTAD with symmetric spiro-bifluorene unit has dominated the investigation of hole-transporting material (HTM) for efficient perovskite solar cells (PSCs) despite of its low intrinsic hole conductivity and instability. In this study, we designed and synthesized three asymmetric spiro-phenylpyrazole/fluorene base HTMs, namely: WY-1, WY-2 and WY-3. They exhibit excellent electrochemical properties and hole conductivities. Moreover, the PSC based on WY-1 exhibits the highest power conversion efficiency (PCE) of 14.2%, which is comparable to the control device employing spiro-OMeTAD as HTM (14.8%). These results pave the way to further optimization of both molecular design and device performance of the spiro-based HTMs.

This review is aimed at the current research progression of a unique class of Pt(II) metal complexes bearing at least one azolate‐containing bidentate chelate. The azole fragment can link to a neutral heteroaromatic entity or another azole and form bidentate chelates, such as monoanionic 3‐pyridyl‐1H‐pyrazole and derivatives, dianionic 3,3′‐bi‐1H‐pyrazole, 3,3′‐(1‐methylethylidene)‐bis‐1H‐pyrazole, and their analogs. These azole‐containing chelates readily react with a variety of Pt(II) reagents to afford the corresponding bis‐bidentate Pt(II) complexes. Most of them were highly emissive in solution, doped polymer matrix, thin film, and even as crystal or powder, due to the high ligand field strength exerted by these chelates and their high propensity in forming the singular square‐planar architecture and intermolecular aggregates with substantially strengthened Pt⋯Pt interaction, according to their structural design. Therefore, they hold bright prospects in academic research and future optoelectronic applications such as organic light‐emitting diodes.

A series of spiro-arranged hole-transporting materials are designed and synthesized by incorporating a substituted phenylpyrazole unit to the orthogonal dibenzosuberene core unit, which are named as THY-1 to THY-5. All of them exhibit good optical, electrochemical, and electronic properties as needed for HTMs, despite the distinctive morphologies observed for the spin-casted thin film. A perovskite solar cell based on THY-5 exhibits the highest power conversion efficiency of 15.83%, which is comparable to that of the N2,N2, N2 0 ,N2 0 ,N7,N7,N7 0 ,N7 0 -octakis(4-methoxyphenyl)-9,9 0 -spirobi[9H-fluorene]-2,2 0 ,7,7 0 -tetramine (Spiro-OMeTAD) reference device (16.22%) fabricated using identical architecture.