Optoelectronic processes in covalent organic frameworks

Abstract

Covalent organic frameworks (COFs) are crystalline porous materials constructed from molecular building blocks using diverse linkage chemistries. The image illustrates electron transfer in a COF-based donor–acceptor system. Image by Nanosystems Initiative Munich.

Chemically Stable Polyarylether-Based Metallophthalocyanine Frameworks with High Carrier Mobilities for Capacitive Energy Storage

“…To evaluate their carrier mobility, Hall effect measurements were conducted at room temperature after depositing four gold electrodes on the top of the COF films on Si/SiO2 (Figure S30). The results reveal that all PAE-PcM COFs are p-type semiconductors with inferred average charge carrier densities of 7.2(±1.8)10 12 , 2.4(±1.5)10 12 , and 0.7(±0.4)10 12 cm −3 for PAE-PcCu, -PcNi and -PcCo, respectively. The corresponding Hall mobility in the dc limit shows that PAE-PcCo has the highest carrier mobility of ~19.4 (±5.1) cm 2 V -1 s -1 , while the carrier mobility of PAE-PcNi and PAE-PcCu are 3.2(±1.9) and 3.2(±0.2)10 -1 cm 2 V -1 s -1 , respectively (Figure S31).…”

“…In recent years, high charge carrier mobility has also been successfully realized in a number of two-dimensional (2D) COFs which exhibit outstanding (opto)electronic properties. [11][12][13][14] In order to broaden their real applications in memory devices, 15-17 photo-/electrocatalyses, [18][19][20][21] chemiresistors, [22][23] energy storage, [24][25] among others, imparting chemical robustness in these 2D COFs is of imperative importance. Synthetic chemistry to construct robust 2D COFs with high charge carrier mobility is limited, with only a few reported examples using pyrazine 22,[26][27] or olefin 28 as the linkages.…”

“…[33][34][35][36][37] Compared with bulk powders, continuous, oriented COF thin films could potentially reduce the interference of grain boundary resistance on their intrinsic (opto)electronic properties. 12 In the past few years, preparation of free-standing and polycrystalline COF thin films has been made possible via air-liquid 38 and liquid-liquid [39][40] interfacial synthesis. However, most mobilityevaluating device fabrications based on these films require harsh processing procedures, such as metal electrode deposition at high vacuum/temperature and wet-chemistry mask etching.…”

Molecular‐Rotor‐Driven Advanced Porous Materials

“…Over the last three decades,n umerous advanced porous materials (APMs) have been developed. Constructed from structure-encoded building blocks,A PMs such as metalorganic frameworks (MOFs), [1][2][3][4][5][6] covalent organic frameworks (COFs), [7][8][9][10][11][12][13][14] porous organic polymers (POPs), [15][16][17] hydrogen-bonded organic frameworks (HOFs), [18][19][20][21] and porous molecular solids [22,23] have performed exceptionally in many aspects of science and technology.S pecifically,t he controlled pore sizes and surface areas of APMs are advantageous for areas such as molecular adsorption and separation, [24][25][26][27][28][29][30] heterogeneous catalysis, [31][32][33][34][35][36][37] and chemical sensing. [38][39][40] More importantly,integrating moving elements,such as molecular rotors (i.e.amolecular component that usually consists of astator and arotator, where the latter can display rotational dynamics), into the robust frameworks of APMs forms molecular-rotor-driven advanced porous materials (MR-APMs).…”

A Heteromeric Carboxylic Acid Based Single‐Crystalline Crosslinked Organic Framework

“…Developing covalently connected porous organic framework materials with high crystallinity, [1] good chemical stability, [2] and large porosity [3] is highly desired to not only establish precise structure-property relationships between porous materials and sorbates, but also advance their practical applications in gas separation, [4] catalysis, [5] and optoelectronics. [6] While one approach of fine-tuning the reversible reactions to obtain single-crystalline covalent organic frameworks [7] (COFs) has been demonstrated successful, [1b] the small crystal sizes of COFs often limit their diffraction data quality to fully unveil the detailed atomic level information. [8] Another emerging approach to generate single-crystalline porous organic materials is covalently crosslinking hydrogenbond pre-organized molecular crystals.…”