Hybrid Solar Cell/Triboelectric Nanogenerator Based on Stable Two‐Dimensional Covalent Organic Frameworks

Covalent organic frameworks (COFs) are a promising class of reticular materials with wide‐ranging applications due to their high surface area and composition. This study focuses on the synthesis and optoelectronic properties of 2D‐ketoenamine‐based COF TpPa1, evaluating its potential as an active layer in photovoltaic devices. Films were grown on TiO 2 substrates via in situ nucleation, resulting in defect‐free, stable, homogeneous thin layers. Computational methods were employed to corroborate the experimental determination of the band gap (1.8 eV, close to 1.75 eV theoretical value) and provide the electronic band structure. Computational study confirms COF layer is arranged in an inclined stacking configuration, explaining the mismatch between simulated and experimental XRD patterns. GIWAXS and DFT analyses revealed that synthesis conditions and substrate interactions influence the stacking and stability of the keto group. XANES and EXAFS studies confirmed strong interactions between TiO 2 and the COF, including Ti─O bonds elongation. COF was integrated into a hybrid solar cell/triboelectric nanogenerator (TENG) system. The solar cell achieved a months‐durable short‐circuit current density of 22.14 µA cm − 2 . Transparent PLA‐based TENG harvested energy from water droplets, generating 44 V, 1.44 µA, and 23 µW peak power. This study demonstrated the use of stable 2D COF films as photoactive layers for integration into hybrid nanoenergy‐generating devices.