Porous organic polymers (POPs) are organic macromolecules that are considered emerging materials because of their high specific surface areas, tunable porosities, low densities, high chemical and thermal stabilities, variable compositions, convenient post-functionalization, extended π-conjugations, and their high contents of carbon, nitrogen, oxygen, and other non-metallic atoms. POPs have been classified into four types: covalent triazine frameworks (CTFs), hypercrosslinked polymers (HCPs), covalent organic frameworks (COFs), and conjugated microporous polymers (CMPs). These materials have potential applications in, for example, gas capture/separation, energy storage, H₂ production from water, photocatalysis, chemical sensing, perovskite solar cells, water treatment, optical devices, and biomedicine. In this review, we provide an overview of recent reports describing the preparation and various applications of POPs.

The preparation of hybrid nanocomposite materials derived from polyhedral oligomeric silsesquioxane (POSS) nanoparticles and polyimide (PI) has recently attracted much attention from both academia and industry, because such materials can display low water absorption, high thermal stability, good mechanical characteristics, low dielectric constant, flame retardance, chemical resistance, thermo-redox stability, surface hydrophobicity, and excellent electrical properties. Herein, we discussed the various methods that have been used to insert POSS nanoparticles into PI matrices, through covalent chemical bonding and physical blending, as well as the influence of the POSS units on the physical properties of the PIs.

In this work, two-dimensional conjugated covalent organic frameworks (2D-COF) based on a building block of tetraphenylethylene are successfully developed. Bicarbazole and pyrene moieties are respectively coupled with 4,4′,4′′,4′′′-(ethane-1,1,2,2-tetrayl)tetranilino (ETTA) via [4 + 4] solvothermal condensation conditions of 3,3′,6,6′-tetraformyl-9,9′-bicarbazole (Car-4CHO) and 1,3,6,8-tetrakis(4-formylphenyl)pyrene (TFPPy) to afford Car-ETTA and TFPPy-ETTA COFs. According to thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and N₂ adsorption and desorption measurements, both Car-ETTA and TFPPy-ETTA COFs exhibit excellent thermal stability, highly crystalline structure, and high specific surface area, respectively. These findings are supported by force field and ab initio calculations. Furthermore, successful applications of these COFs in perovskite solar cells (PVSCs) are demonstrated owing to their well-conjugated properties and π–π interactions. While serving as interlayers in the devices, these COFs could effectively promote the interfacial charge dynamic to further optimize the resulting performance. Besides, certain interaction between COFs and perovskite also leads to an improved morphology and crystallinity of the perovskite layer, presenting defect passivation capability. As a result, we show that the performance of the COF-modified PVSC could be improved from 17.40 to 19.80%.